DW  J  C^i 

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I  UNIVERSITY  OF  CALIFORNIA 
W.  ANDREW  ^dpT 
^  SMITH  ^^ 
HALLIDIC: 


. 


TOOL-STEEL. 


TOOL-STEEL: 

A  CONCISE  HANDBOOK 


ON 


TOOL-STEEL  IN  GENERAL, 


ITS   TREATMENT    IN   THE    OPERATIONS   OF   FORGING,  ANNEALING, 
HARDENING,  TEMPERING,  ETC. 

AND  THE  APPLIANCES  THEREFOR, 


BY 


OTTO  THALLNER, 

IRON-MASTER  AND  MANAGER  *IN  CHIEF  OF  THE  TOOL-STEEL  WORKS, 
BISMARCKHUTTE  ON  THE  SAALE,   GERMANY. 


AUTHORIZED  TRANSLATION  FROM  THE  GERMAN, 

BY 

WILLIAM  T,  BRANNT, 


ILLUSTRATED  BY  SIXTY-NINE  ENGRAVINGS. 


i  ur        TY  j 

V 


PHILADELPHIA: 

HENRY  CAREY  BAIRD  &  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS, 
810  WALNUT  STREET. 

LONDON : 

SAMPSON  LOW,  MARSTON  &  CO.,  LIMITED, 

ST.  DUNSTAN'S  HOUSE,  FETTER  LANE,  FLEET  STREET. 

1902. 


HALL1D1E 


COPYRIGHT,  BY 

HENRY  CAREY  BAIRD  &  CO. 
1902. 


PRINTED  AT  THE 

WICKERSHAM  PRINTING  HOUSE, 

53  and  55  North  Queen  Street, 

LANCASTER,  PA.,  U.  S.  A. 


PREFACE. 


THE  changes  which  tool-steel  undergoes  by  the  various 
operations  of  forging,  annealing,  hardening,  tempering,  etc., 
have  theoretically  been  established  by  Ledebur,  Wedding, 
Reiser,  Osmond,  and  others. 

The  rules,  which  have  been  deduced  from  theory,  of  what 
has  to  be  observed  in  the  above-mentioned  operations  are  in 
themselves  of  a  simple  nature  and  readily  comprehended, 
and  a  more  universal  knowledge  of  them  has  been  diffused 
by  the  scientific  publications  of  the  above-mentioned  writers, 
as  well  as  by  the  so-called  "  directions  for  the  treatment "  of 
the  steel,  which  nearly  every  manufacturer  of  tool-steel 
furnishes  to  his  customers. 

The  almost  sole  object  of  these  directions  is  to  promote  a 
more  intimate  knowledge  of  steel  and  its  treatment  in  the 
manufacture  of  tools  among  those  who  are  especially 
entrusted  with  it,  but,  as  a  rule,  an  explanation  of  "  how 
and  by  what  means "  their  observance  is  to  be  effected  is 
wanting. 

The  steel  recommended  by  them  is  not  seldom  invested 
with  mysterious  properties,  and  encouragement  is  frequently 
given  to  the  continuance  of  primitive  appliances,  but  little 
suitable  for  the  purpose  and  difficult  to  attend. 

In  these  directions  the  pith  of  the  matter  is  very  seldom 
treated  of,  or  only  in  a  very  brief  way,  so  that  the  changes 
which  the  steel  undergoes  in  the  various  operations  of  the 
manufacture  of  tools  remain,  as  a  rule,  not  understood,  and 
there  is  no  probability  of  the  mind  being  directed  towards 
the  necessity  of  suitable  working  appliances. 

Publications  on  this  subject  derived  from  practice  are  also 
scarce,  because  experiences  gathered  in  this  line  are  prefer- 
ably kept  secret. 


VI  PREFACE. 

These  conditions  apparently  explain  the  limited  general 
diffusion  of  a  knowledge  of  practically  approved  appliances 
and  working  processes,  in  consequence  of  which  master- 
workman  and  manufacturer  are  frequently  placed  in  the 
disagreeable  position  of  having  to  desist  from  making  the 
most  of  the  highest  efficiencies  attainable  in  tools,  or  are 
forced  to  work  with  a  greater  expense  of  time,  money  and 
material  than  would  otherwise  be  necessary. 

The  master-workman  and  the  workmen  entrusted  with 
the  manufacture  of  tools  are  under  the  necessity  of  gather- 
ing experience  from  their  own  practice,  and  it  is  largely  left 
to  themselves  to  devise  appliances  required  for  successful 
working  without  having  at  their  disposal  anything  that  will 
give  them  a  clue  to  how  it  is  to  be  done. 

It  was  especially  the  latter  condition  that  induced  me  to 
write  this  small  work. 

It  is  chiefly  intended  as  a  guide  to  the  master-workman 
and  the  intelligent  tool-maker,  and,  in  accordance  with  this 
object,  is  exclusively  adapted  to  practical  needs. 

'As  sources  of  the  explanations  derived  from  theory, 
which  have  been  incorporated  into  the  book,  the  scientific 
works  and  separate  publications  of  the  previously  men- 
tioned authors  have  served. 

.The  general  arrangement  of  the  material  has  been 
modeled  after  the  excellent  work  by  F.  Reiser:  "  Das 
Harten  des  Stahles  in  Theorie  und  Praxis  "  ("  Hardening 
of  Steel  in  Theory  and  Practice  "). 

The  directions  and  working  appliances  collected  in  the 
book  have  throughout  been  taken  from  practice,  and  are 
intended  to  assist  master-workmen  and  workmen  employed 
ini  the  practical  execution  of  the  various  operations  in  the 
manufacture  of  tools,  in  their  occupation,  which  demands 
varied  knowledge  and  experience. 

THE  AUTHOR. 

BlSMARCKHUETTE  ON  SAALE. 


CONTENTS. 


INTRODUCTION. 

PAGE 

Products  of  iron-works  used  in  the  manufacture  of  tools;  Tool-steel  and 
various  designations  of  it 1 

Crucible  steel  the  most  noble  product  of  the  manufacture  of  tool-steel; 
Weld  steel  and  the  product  brought  into  commerce  under  this  name  ...  2 

I. 

COMPOSITION  OF  TOOL-STEEL  AND  ITS  CLASSIFICATION  ACCORDING  TO  IT. 

Definition  of  steel;  Various  forms  in  which  carbon  occurs  in  iron; 
Hardening  carbon  3 

Carbide;  Graphitic  carbon;  Accidental  admixtures  in  steel;  On  what  the 
quality  of  steel  depends 4 

Quantity  of  injurious  admixtures  in  steel;  Silicon  in  crucible  steel;  In- 
tentionally added  admixtures 5 

Manganese ;  Manganese  steel ;  Properties  of  actual  manganese  steel ; 
Tungsten  6 

Properties  of  steel  to  which  tungsten  has  been  added;  Chromium  7 

Nickel;  Molybdenum,  titanium  and  vanadium...... 8 

II. 

CLASSIFICATION  OF  TOOL-STEEL  ACCORDING  TO  THE  DEGREE  OF  HARDNESS 

AND  THE  PURPOSE  FOR  WHICH  IT  IS  TO  BE  USED. 

Groups  of  commercial  tool-steel;  Tool-steel  which  acquires  its  hardness 
exclusively  from  a  content  of  carbon;  Tool-steel  which  in  addition  to 
carbon  contains  admixtures  increasing  the  hardness,  also  called  special 

steel 9 

Modes  of  labeling  tool-steel;  Designations  for  the  degree  of  hardness 10 

Selection  of  tool-steel  for  a  determined  purpose;  Standard  in  practice  for 
the  useful  effect  of  the  finished  tool;  Less  attention  required  in  working 
soft  steel 11 

(vii) 


Vlll  CONTENTS. 

PAGE 

Classification  of  steel  according  to  the  degree  of  hardness  and  the  pur- 
poses for  which  it  is  to  be  employed  as  in  use  in  Bismarck  huette;  Special 
steels 12 

Natural  hard  steel;  Special  turning  steel;  Magnet  steel;  Composition  of 
self-hardened  steel  and  of  very  hard  special  turning  steel  13 

Composition  of  magnet  steel ;  Tool  steel  for  definite  purposes 14 

Soft-centred  or  mild-centred  steel .  and  mode  of  producing  it 15 

III. 

OBSERVATIONS  ON  THE  EXTERNAL  APPEARANCE  OF  COMMERCIAL 

TOOL-STEEL. 

Defects  which  the  surface  of  the  steel  may  show;  Scales;  Cracks;  Seams.     16 
Edge  cracks;  Appearance  of  the  fracture;  Structure  of  soft  and  of  hard 

steel 17 

Defects  which  may  be  observed  on  the  surfaces  of  the  fractures  of  tool- 
steel;  Flaws  or  blisters;  Spots  due  to  liquation;  Flaws  in  the  centre  of 
the  steel  and  their  cause  18 

IV. 

OBSERVATIONS  ON  THE  FRACTURE  OF  STEEL,  WITH  EEGARD  TO  THE  STRUC- 
TURE IN  THE  HARDENED  AND  NON-HARDENED  STATES. 

Difference  in  the  appearance  of  the  structure  of  steel  according  to  how  it 
has  been  worked 19 

Conditions  on  which  the  appearance  of  the  fracture  of  unhardened  steel 
may  depend 20 

Conditions  on  which  the  appearance  of  the  fracture  of  hardened  steel  is 
dependent;  Tables  showing  the  influence  of  the  various  degrees  of 
temperature  upon  hardened  and  unhardened  steel,  and  their  general 
application  in  practice 21 

V. 

PRACTICE  OF  THE  FIRE-TREATMENT  OF  STEEL. 

Purpose  of  the  repeated  heating  of  steel  in  the  manufacture  of  tools 22 

Proper  adaptation  of  the  appliances  for  heating;  Choice  of  fuel;  Disad- 
vantages which  may  result  from  the  use  of  certain  fuels 23 

Hard  coke  and  furnace  for  heating  the  steel 24 

Smith-coal  or  forge  coal  25 

Effect  produced  by  a  content  of  sulphur  in  the  coal;  Coke  dust  26 


CONTENTS.  IX 

PAGE 

Location  of  the  highest  degree  of  heat  developed  in  an  open  fire;  Diffi- 
culties encountered  in  heating  in  an  open  fire  27 

Conversion  of  an  open  fire  into  a  provisional  furnace 28 

Disagreeable  feature  in  heating  cutters;  Construction  of  a  muffle  in  the 

open  fire 29 

Unsuitableness  of  mild  soft  coke  for  forging  and  hardening  from  open 

fires;  Advantages  of  charcoal  for  open  fires  30 

Disadvantages  resulting  from  the  action  of  the  blast  upon  tool-steel  or  the 

finished  tool 31 

Mode  of  protecting  the  steel  from  the  action  of  the  blast;  Weakening  the 
effect  of  the  blast;  Remedy  for  the  attacks  of  the  air  upon  the  surface 

of  the  steel 32 

Disadvantages  of  open  fires  in  making  or  repairing  a  large  number  of 
tools;  Importance  of  the  influence  of  light  in  judging  the  degree  of 

temperature  of  the  steel 33 

Location  in  the  works  of  the  devices  for  forging  and  hardening  tools; 

Avoidance  of  drawbacks  due  to  heating  the  steel  in  an  open  fire 34 

Most  simple  type  of  furnace;  Construction  of  a  furnace  to  be  operated 

with  coke 35 

Construction  of  a  furnace  to  be  operated  with  charcoal  38 

Furnace  for  heating  long  articles 39 

Construction  of  furnaces  to  be  fitted  for  coal 40 

Conversion  of  a  furnace  into  a  regular  muffle  furnace 41 

Construction  of  a  muffle  furnace  to  be  worked  with  charcoal 42 

Muffle  furnaces,  the  muffles  of  which  are  heated  by  gas;  Heating  muffles 

of  refractory  clay  43 

Ordinary  forging  reverberatory  furnace * 44 

Small  reverberatory  furnace  for  forging  and  hardening  operations  on  a 

small  scale;  Reverberatory  furnace  with  two  hearths 45 

Small  reverberatory  furnace  with  step-grate  and  two  hearths;  Reverbera- 
tory furnace  with  a  fire-place  patented  by  Gasteiger,  of  Vienna  ... 47 

Reverberatory  furnace  with  muffle 48 

VI. 

APPLIANCES  FOB  ANNEALING  STEEL. 

Changes  in  the  properties  of  strength  of  steel;  Forging  strains  and  their 
removal  by  annealing;  General  rule  applying  to  annealing;  Protection 
of  tool-steel  from  the  air  by  annealing  it  in  vessels 49 


X  CONTENTS. 

PAGE 

Hints  for  the  practical  execution  of  annealing;  Annealing  in  boxes;  Con- 
struction of  an  annealing  furnace  for  forged  pieces  50 

Furnace  for  annealing  steel  in  an  annealing  pot  or  in  annealing  boxes 52 

Control  of  the  result  of  the  annealing  operation 54 

Annealing  furnace  for  annealing  long  articles  55 

VII. 
APPLIANCES  FOR  HARDENING  STEEL. 

Importance  of  thoroughly  uniform  heating;  Disadvantages  of  imperfect 
heating  appliances 55 

Hints  for  the  choice  of  suitable  appliances;  Furnaces  suitable  for  hard- 
ening   56 

Methods  for  hardening  tools  in  a  bath  of  molten  metal  or  in  a  bath  of 
fused  salts;  Possibility  of  overheating  of  the  melted  mass 57 

Furnace  and  crucible  for  melting  the  metals  or  salts;  Advantages  of  the 
use  of  a  pyrometer;  Disadvantages  which  may  arise  from  heating  steel 
in  melted  lead 58 

Mode  of  preventing  melted  lead  from  adhering  to  some  portions  of  the 
tool;  Heating  steel  in  fused  salts;  Mixture  of  salts  59 

Fusion  of  the  salts;  Addition  of  yellow  prussiate  of  potash;  Preparation 
of  the  articles  to  be  heated;  Suspension  of  the  articles  in  the  melt 60 

Unequal  heating  of  the  melt  and  its  detection;  Advantages  of  heating 
tools  in  melted  salt 61 

VIII. 
HARDENING  OF  TOOL-STEEL  IN  GENERAL. 

What  is  understood  by  hardening;  Hardening  temperature;  Definition  of 
temper  color;  Appearance  of  the  temper  colors  62 

General  custom  of  tempering  finished  tools;  Requirements  for  the  appear- 
ance of  the  temper  colors;  Conditions  to  which  the  changes  steel  under- 
goes in  hardening  are  chiefly  due  63 

Changes  in  the  dimensions  of  the  steel,  illustrated  64 

Strains  in  the  steel  before  it  is  hardened  not  removed  by  simply  heating 
in  hardening;  Practical  utilization  of  the  property  of  steel  of  assuming 
fixed  dimensions  in  hardening  operations  succeeding  one  another  65 

Observations  on  the  fractures  of  tool-steel  of  the  same  degree  of  hardness 
notched  at  various  distances  from  each  other,  and  then  hardened  and 
broken  on  the  notched  places 66 


CONTENTS.  XI 

PAGE 

Illustration  of  the  cross-section  of  steel  not  hardened  and  of  the  cross- 
section  of  the  same  steel  hardened  67 

Cause  of  cracking;  Cracking  from  the  interior 68 

Observations  on  the  fracture  of  hardened  steel  of  a  larger  cross-section; 

Severance  of  the  corners  of  a  cube,  illustrated 69 

Examples  of  the  force  of  the  strain  in  forming  cracks,  illustrated 70 

Distortions  of  the  steel  caused  by  strains,  illustrated 71 

Change  in  the  cross-section  of  tools  by  hardening;  Prevention  of  cracking; 
Influence  of  manganese  upon  the  change  in  volume  of  the  steel  in 
hardening 72 

IX. 
HARDENING  OF  TOOLS  WHICH  ABE  TO  BE  HABDENED  IN  THEIB  ENTIRETY. 

Cause  of  cracking  and  means  of  avoiding  it;  Prevention  of  cracking  by 

letting-down ;    Portions   of  tools   especially   subject  to   snapping  off; 

Cracking  from  the  interior 73 

Effect  of  letting-down;  Cause  of  the  snapping  off  of  the  teeth  of  a  cutter...  74 
Avoidance  of  superficial  scale-like  separations  on  tools;  Prevention  against 

a  tool  completely  losing  its  hardness  75 

Reheating  in  hot  sand  or  in  hot  water 76 

Process  of  allowing  the  hardened  tool  to  remain  in  the  hardening  bath 

until  it  is  entirely  cold;  Practical  application  of  this  process 77 

Division  of  tools  into  several  sections 78 

Diminution  of  strains  by  boring  out  a  tool;  Main  points  to  be  considered 

in  the  construction  of  a  tool 79 

X. 

HABDENING  OF  TOOLS  WHICH  ARE  ONLY  TO  BE  PARTIALLY  HARDENED. 

Division  of  partial  hardening  into  three  groups  80 

Mode  of  heating;  Overheating  of  broad  cutters;  Powder  for  cooling  off...  81 
Heating  tools  all  over  which  are  to  be  partially  hardened;  Experiment 

with  a  bar  of  steel 82 

Hardening  tools  so  that  there  is  a  gradual  transition  of  the  hardened  into 

the  unhardened  portions 83 


Xll  CONTENTS. 

PAGE 

XL 

COOLING  OF  TOOLS  IN  HARDENING  AND  DEVICES  FOR  THIS  PURPOSE. 

General  rule  for  heating  tools  for  hardening;  Formation  of  steam  in  the 
hardening  bath,  and  its  effect 83 

Hardening  of  especially  large  and  heavy  tools;  Uneven  cooling  before 
hardening,  and  its  effect  84 

Formation  of  cracks  by  catching  the  red-hot  tool  with  cold  tongs,  illus- 
trated by  an  example 85 

Correct  and  incorrect  forms  of  tongs;  Covering  portions  not  to  be  hard- 
ened   86 

Intentional  uneven  cooling  by  covering  portions  of  the  tool,  illustrated  by 
examples 87 

Cooling  of  tools  which  have  to  be  heated  in  their  entirety;  Mode  of  using 
running  water  for  hardening  89 

Use  of  falling  water  for  hardening  and  device  for  this  purpose 90 

Equalization  of  strains  formed  by  hardening,  and  device  for  this  purpose.     91 

Device  for  hardening  if  a  water  conduit  or  running  water  is  not  available.     92 

Object  of  hardening  in  an  ascending  water  jet;  Simultaneous  use  of  a 
falling  and  ascending  water  jet;  Device  for  hardening  in  an  ascending 
water  jet 93 

Method  of  hardening  by  means  of  a  jet  if  the  operation  of  hardening  is  to 
be  effected  in  a  large  reservoir;  Hardening  of  hollow  bodies,  and 
devices  for  that  purpose 95 

XII. 

LIQUIDS  USED  IN  QUENCHING  STEEL. 

Pure  water;  Most  suitable  temperature  of  the  hardening  water;  Com- 
position of  water;  Increase  in  the  heat-conducting  power  of  water  by 
salts  and  acids 97 

Means  for  lessening  the  too  intense  hardening  effect  of  well  or  spring 
water;  Favorable  effect  of  hardening  water  which  has  been  used  for 
some  time;  Hardening  water  mixed  with  soluble  constituents  98 

Common  salt;  Soda  (carbonate  of  soda);  Acids;  Use  of  acidulated  water.     99 

Alcohol;  Soap;  Effects  of  soluble  admixtures  of  organic  nature;  Harden- 
ing water  mixed  with  insoluble  constituents 100 

Hardening  water  mixed  with  oils  or  fats 101 


CONTENTS.  Xlll 

PAGE 

Oils  and  fats;  Precaution  in  using  fat  or  oil  for  hardening;  Metals;  Mer- 
cury    102 

Tin,  zinc  and  lead;  Change  in  the  properties  of  steel  cooled  in  melted 
metals " 103 

Gaseous  cooling  agents;  Solid  bodies  as  cooling  agents 104 

Results  obtained  in  Bismarckhuette  by  experiments  regarding  the  cutting 
power  of  medium  hard  tool-steel  hardened  in  various  cooling  agents...  105 

XIII. 
TEMPERING  OF  HARDENED  STEEL,  AND  DEVICES  FOR  THIS  PURPOSE. 

Yarious  ways  in  which  tempering  may  be  effected;  Tempering  from  the 

interior 105 

Recognition  of  the  advance  of  the  heat  by  the  progression  of  the  temper 
colors;  To  impart  special  toughness  to  a  tool  which  in  use  is  exposed 

to  shock  and  blow  106 

Progression  of  cracks,  illustrated  by  an  example;  Tempering  from  the 

interior 107 

Tempering  from  the  interior  assisted  by  simultaneous  heating  from  the 

outside;  An  error  frequently  committed  in  cooling 108 

Precaution  in  tempering  from  the  outside;  Requisite  for  tempering  tools.  109 
Effect  of  the  duration  of  time  in  tempering,  and  its  practical  utilization; 

Blazing  off  with  oil 110 

Tempering  small  tools  in  oil,  and  device  for  that  purpose Ill 

Tempering  in  an  open  fire,  upon  red-hot  iron  and  by  means  of  a  gas  flame.  112 

Tempering  by  means  of  hot  sand,  and  devices  for  that  purpose 113 

Tempering  of  long  knives  and  furnace  for  that  purpose 114 

Cooling  tempered  tools  115 

Error  frequently  committed  in  tempering  partially  hardened  tools 116 

XIV. 

STRAIGHTENING  TOOLS. 

Methods  by  means  of  which  straightening  may  be  effected;  Cause  of  dis- 
tortion of  tools  during  hardening;  Straightening  claws  and  their  use  .  .  117 

Tools  required  for  straightening;  Straightening  of  tools  by  uneven  heat- 
ing and  cooling  in  tempering  118 


XIV  CONTENTS. 

PAGE 

XV. 

CASE-HARDENING  AND  PREVENTATIVES  AGAINST  SUPERFICIAL  DECARBONI- 
ZATION  AND  OVERHEATING. 

Object  of  case-hardening;  Effect  on  the  structure  of  iron  or  steel  when 

heating  with  carbon  is  effected  at  a  high  temperature 119 

Method  pursued  in  the  operation  of  case-hardening;  Application  of  case- 
hardening  in  practice ..  120- 

Manner  of  packing  a  spindle  which  is  to  be  hard  in  two  places,  illustrated.  121 

Burning  in,  and  mode  of  effecting  this  operation 122 

Hardening  paste  and  its  preparation  , 123 

Dry  hardening  powder  and  its  composition;  Agents  for  cooling  tools 124 

Cooling  of  unevenly  heated   tools;    Compositions  of  suitable   powders; 

Mode  of  applying  the  powder  125 

Mixtures  which  are  to  be  applied  in  a  pasty  condition    126 

Carbon  compounds  in  a  gaseous  form  for  case-hardening;  Use  of  pig-iron 
for  case-hardening  127 

XVI. 

WELDING  OF  STEEL. 

Heating  steel  for  welding 127 

Agents  which  assist  in  the  formation  of  a  soft  layer  on  the  surface  of  the 
steel;  Operation  of  welding 128 

XVII. 

EEGENERATION  OF  STEEL  WHICH  HAS  BEEN  SPOILED  IN  THE  FIRE. 

Steel  burnt  and  overheated 129' 

Mode  of  restoring  the  fine  structure  of  the  steel  when  tools  have  been 
overheated;  Definitions  of  roasted  or  baked  steel,  and  of  dead  steel 130' 

XVIII. 

INVESTIGATIONS  OF  DEFECTS  OF  HARDENED  TOOLS. 

What  experience  in  hardening  includes;  Test  operation  with  one  piece...  131 
Overheating;  Severance  of  cornel's  and  edges  of  larger  tools;  Uncertainty 

and  timidity  in  hardening;  Hints  for  the  inspection  of  tools 132 

Observations  on  the  fracture  of  the  tool;  What  curved  cracks  on  flat  tools 
indicate...,  ..   133 


CONTENTS.  XV 

PAGE 

Failure  due  to  incorrect  cooling;  Tools  cracked  from  the  interior;  Cracks 
or  separation  of  corners;  Edge  cracks;  Uneven  degree  of  hardness 134 

Cause  of  uniform  degree  of  insufficient  hardness;  Soft  spots;  Soft  skin  on 
the  surface  of  a  hardened  tool;  Tools  roasted  or  baked  135 

Defects  noticed  in  using  tools;  Experiments  at  Bismarckhuette  as  to  the 
efficiency  of  tools 13& 

Increase  in  efficiency  by  a  suitable  process  of  cooling;  Defect  very  fre- 
quently observed  on  very  hard  cutting  tools  caused  by  grinding  upon 
hard,  rapidly-revolving  emery  wheels 137 

Defects  of  tools  with  engraved  surfaces;  Notching  of  tools  and  prevention.  138 

Examination  of  tools  which  prove  defective  in  use 139 

XIX. 

IMPROVING  THE  PROPERTIES  OF  STRENGTH  OF  STEEL. 

Object  of  improving  the  properties  of  strength  of  steel;  Properties  of  steel 
rolled  or  forged  at  a  high  temperature;  Effects  of  the  operations  of  hard- 
ening and  tempering 140 

Most  useful  methods  for  improving  and  regulating  the  properties  of 
strength  of  steel 141 

APPENDIX. 

Conditions  which  confront  the  toolsmith  or  locksmith;  Demands  made  on 

foremen  and  workmen  142 

Primitive  character  of  appliances  which  are  frequently  required;  Mode  of 
working  to  be  observed  in  forging,  annealing,  hardening  and  tempering 

tools  frequently  called  for;  Hand  chisels 143 

Hot  and  cold  chisels;  Kivet  chisels  (for  cutting  off  rivet  heads);  Center 

bits 144 

Turning  knives  and  planing  knives;  Roll-turning  knives  145 

Screw-taps  146 

Screw-dies 147 

Broaches;  Spiral  drills  for  metal 148 

Common  drills;  Cutters 149 

Method  of  cooling  wood-cutters  of  harder  steel  in  molten  metal ;   Pipe 

cutters 152 

Milling  tools;  Hammers  (hand  hammers,  riveting  hammers,  sledge  ham- 
mers, etc.)  153 


XVI  CONTENTS. 

PAGE 

Hammer  swages 154 

Cause  of  defects  in  swages 155 

Hound  and  circular  shear  knives  (roll  shear  knives);  Shear  knives 156 

Device  for  letting  down  shear  knives 158 

Machine  knives  for  cutting  paper,  knives  for  splitting  leather,  planing 

and  cutting  knives  for  wood;  Stamping  knives  for  stamping  out  leather 

(soles  and  heels),  paper,  pasteboard,  bristolboard,  etc 159 

Circular  knives  (simple,  straight  and  plate  knives);  Punches  and  dies....  160 

Stamps  and  dies;  Punches  and  dies  for  perforating  holes  in  metals 162 

Mandrils  for  drawing  metal  cases  and  tubes;  Draw  plates 164 

Pillow  blocks  and  pivots;  Stone-working  tools;  Tools  for  the  manufacture 

of  nails 165 

Balls;  Hardening  small  balls  used  for  bearings;  Difficulty  in  hardening 

large  balls  166 

Tongs  for  handling  balls;  Device  for  hardening  large  balls 167 

Rolls;  Process  of  hardening  a  large  roll,  illustrated  by  an  example 168 

Appliance  for  hardening  the  roll 171 

Table  for  the  conversion  of  centimeters  to  inches 172 

Index...  ,.  173 


TOOL-STEEL. 


INTRODUCTION. 

IN  a  wider  sense,  nearly  all  the  products  of  iron-works, 
commencing  with  pig  iron  up  to  weld-iron  and  ingot-iron, 
which  are  not  capable  of  being  hardened,  are  employed  in 
the  manufacture  of  tools.  However,  in  a  narrower  sense, 
iron  which  is  capable  of  being  hardened,  i.  e.,  steel,  has, 
under  the  general  designation  of  tool-steel,  to  be  chiefly 
taken  into  consideration  for  the  manufacture  of  tools. 

In  many  cases  tool-steel  is  still  more  closely  designated 
according  to  the  smelting  processes  from  which  it  has 
resulted,  such  as  ingot-steel,  weld-steel ;  or  according  to  the 
method  of  production,  such  as  Bessemer  steel,  Martin  steel, 
crucible  steel,  puddled  steel,  shear  steel,  etc.;  further  accord- 
ing to  certain  peculiarities,  such  as  natural  or  self-hardened 
steel,  hard-centred  steel,  soft-centred  or  mild-centred  steel, 
tungsten-steel,  chrome-steel,  nickel-steel,  etc.;  and  finally, 
according  to  the  purposes  to  which  it  is  to  be  applied,  such 
as  knife-steel,  scythe-steel,  magnet-steel,  punch-steel,  chisel- 
steel,  etc. 

Beside  the  above-mentioned  designations,  there  are  also 
in  use  several  of  an  allegorical  nature,  such  as  diamond- 
steel,  self-hardener,  boreas,  atlas-steel,  universal  steel,  etc., 
and  others  which  intimate  an  alloy — which,  however,  as  a 
rule,  cannot  be  authenticated — to  improve  the  quality  of 

(1) 


2  TOOL-STEEL. 

the  steel,  such  as  titanium-steel,  aluminium-steel,  vanadium- 
steel,  etc. 

The  most  noble  product  of  the  manufacture  of  tool-steel 
is  crucible-steel,  i.  e.,  steel  made  by  remelting  in  a  crucible 
basis-materials  in  themselves  very  pure  and  of  excellent 
quality.  The  object  of  this  process  is  to  obtain  a  thoroughly 
uniform  product  as  free  as  possible  from  injurious  admix- 
tures, and  in  the  preparation  of  it  every  precaution  is  taken 
to  avoid  mistakes  which  might  impair  the  quality  of  the 
finished  tool-steel.  Hence  crucible-steel  is  rather  expensive 
and  for  this  reason  ingot-steel  produced  by  the  Bessemer 
and  Martin  processes  is  largely  used  for  inferior  purposes. 

This  steel  is  generally  brought  into  commerce  under  the 
simple  designation  of  "  cast  steel,"  and  by  many  consumers 
is  worked  in  good  faith  as  crucible  steel. 

The  steel  for  the  manufacture  of  tools  brought  into  com- 
merce under  the  name  of  "  weld-steel "  is  practically,  as  a 
rule,  steel  capable  of  being  welded  or  hardened  without 
regard  as  to  whether  or  not  it  is  weld-steel  according  to  the 
smelting  processes  by  means  of  which  it  has  been  produced. 
In  most  cases  the  product  brought  into  commerce  under 
the  name  of  weld-steel  is  "  weldable  ingot  steel." 


I. 


COMPOSITION  OF  TOOL-STEEL  AND  ITS  CLASSI- 
FICATION ACCORDING  TO  IT. 

IRON,  which  by  being  heated  to  a  red  heat  and  suddenly 
cooled,  has  acquired  such  hardness  that  it  is  not  attacked 
by  a  file  is,  generally  speaking,  called  steel.  This  property 
of  iron  results  from  a  content  of  carbon  which  may  amount 
to  between  0.5  and  2  per  cent. 

Iron  with  less  than  0.5  per  cent,  carbon  *  does  not 
acquire  such  a  high  degree  of  hardness,  and  with  more 
than  2  per  cent,  carbon,  it  becomes  pig-iron,  and  beside 
losing  the  capacity  of  being  hardened,  also  loses  the  prop- 
erty of  malleability. 

It  has  been  shown  by  scientific  researches  that  in  iron, 
carbon  occurs  in  various  forms,  the  most  important  of  which 
are  as  follows : 

a.  Carbon  fixed  to  the  iron  forming  a  chemical  combina- 
tion with  it  (hardening  carbon). 

This  form  of  carbon  appears  to  be  the  carrier  of  the  hard- 
ening capacity  in  steel,  and  the  process  which  takes  place 
thereby  has  scientifically  been  determined  as  follows : 

When  iron  containing  carbon  is  allowed  slowly  to  cool 

*  The  transition  from  iron  incapable  of  being  hardened  to  steel  which  can  be 
hardened  is  a  gradual  one,  and  the  limit  between  them  cannot  be  expressed  by 
the  content  of  carbon  alone.  The  limit  mentioned  above  refers  to  crucible- 
steel  of  the  lowest  degree  of  hardness  used  for  hardened  tools. 

(3) 


4  TOOL-STEEL. 

from  the  melting  temperature,  the  carbon  present  forms 
with  a  portion  of  the  iron  a  combination  which  is  net-like 
diffused  throughout  the  iron.  (Carbide.) 

When  such  iron  is  heated  to  a  cherry-red  heat,  the  carbon 
present  is  uniformly  absorbed  (dissolved)  by  the  iron  and 
becomes  hardening  carbon.  By  quickly  cooling  the  heated 
steel  the  carbon  becomes  fixed  in  this  state,  and  the  steel  is 
hardened.  If,  however,  the  steel  is  allowed  to  cool  slowly, 
the  carbon  is  separated  from  its  uniform  combination  with 
the  iron  and  again  forms  with  a  portion  of  the  latter  the 
net-like  diffused  carbide. 

The  larger  the  quantity  of  carbon  (carbide)  present,  the 
more  of  it  can  during  the  process  of  hardening  be  converted 
into  hardening  carbon,  and  the  greater  will  be  the  degree 
of  hardness  which  the  steel  acquires. 

6.  The  carbon  may  occur  in  a  free  form  visibly  imbedded 
between  the  particles  of  iron  (graphite). 

Graphitic  carbon  cannot  be  converted  by  the  operation 
of  hardening  into  hardening  carbon,  and  hence  does  not  in- 
duce hardening.  It  is  a  chief  constituent  of  gray  pig  iron. 
It  occurs  very  seldom  in  tool-steel  and,  when  present,  exerts 
an  injurious  influence  upon  its  quality. 

Besides  iron  and  carbon,  steel  contains  other  substances 
which  are  either  accidental  admixtures,  or  are  added  for  a 
special  purpose.  Phosphorus,  sulphur,  copper  and  arsenic 
are  the  principal  accidental  admixtures,  and  they  exert 
always  an  injurious  effect.  A  few  hundredths  of  one  per 
cent,  of  either  of  these  substances  suffice  to  render  steel 
partially  or  entirely  unfit  for  the  manufacture  of  tools. 
The  quality  of  steel  is  dependent  on  the  quantity  of  injur- 
ious constituents  it  contains,  and  the  total  sum  of  them 
may  serve  as  an  expression  in  figures  of  its  value. 


COMPOSITION    OF    TOOL-STEEL.  5 

111  tool-steel  it  is  sought  to  avoid,  as  much  as  possible, 
the  occurrence  of  injurious  impurities,  and  in  its  production 
materials  free  from  them  are,  as  a  rule,  only  used.  Hence, 
the  quantity  of  injurious  admixtures  in  tool-steel  is  never 
so  large  that  their  presence  could  at  once  be  inferred  from 
its  physical  behavior  in  working. 

No  matter  what  the  nature  of  the  injurious  admixtures 
may  be,  it  shows  itself  chiefly  by  brittleness  in  tool-steel 
when  in  the  hardened  state,  and  with  an  abundance  of  im- 
purities, also  in  the  unhardened  state.* 

Crucible  cast-steel  generally  contains  silicon  as  a  fortu- 
itous admixture  which  has  been  absorbed  by  melting  in 
the  crucible.  This  content  of  silicon  is,  however,  seldom 
so  great  as  to  exert  an  essential  influence  upon  the  quality 
of  the  steel.  A  higher  content  of  silicon  promotes  the 
edge-holding  capacity,  but  also  increases  the  brittleness 
of  the  steel,  and  is  injurious  when  it  causes  a  partial 
separation  of  the  carbon  in  graphitic  form.  The  fracture 
of  such  steel  shows  a  dark  grain. 

Intentionally  are  added  to  tool-steel  the  following  metals, 
with  the  expectation  of  improving  thereby  the  quality  : 

*  Numerous  chemical  and  practical  investigations  in  Bismarckhiitte  regard- 
ing the  qualitative  value  of  tool-steel  dependent  on  the  degree  of  impurities 
have  shown  that  the  total  amount  of  phosphorus,  sulphur  and  copper  should 
not  exceed  0.06  per  cent.,  if  the  material  is,  according  to  practical  conditions, 
to  be  classed  as  "  very  good"  tool-steel.  Steel  which  contains  a  total  of  0.10 
per  cent,  of  phosphorus,  sulphur  and  copper  may  be  designated  as  "good" 
tool-steel,  and  when  it  contains  more  than  this  amount,  as  "  medium"  to 
"bad"  tool-steel. 

Since  the  tenacity  of  steel  decreases  with  an  increase  in  the  content  of  car- 
bon, the  effect  of  injurious  admixtures  is  essentially  greater  in  harder  than  iw 
softer  steel,  so  that  the  figures  given  above  may  be  somewhat  raised  with  soft 
steel  and  somewhat  lowered  with  hard  steel. 


6  TOOL-STEEL, 

Manganese,  tungsten,  chromium,  nick-el,  -and  more  seldom 
molybdenum  and  other  metals, 

MANGANESE. 

Every  kind  of  tool-steel  contains  manganese,  the  quan- 
tity in  the  ordinary  product  being  from  0.2  to  0.5  per  cent 
Within  these  narrow  limits  manganese  does  not  exert  any 
considerable  influence  upon  the  properties  of  the  steel,  the 
strength,  hardness  and  cutting  power  being  slightly  in- 
creased. On  the  other  hand,  it  is  the  task  of  manganese  to 
remove  or  fix  during  the  fusing  processes  the  gases  and  the 
oxides  which  are  present  in  great  abundance  in  liquid 
steel,  and  thus  cause  the  production  of  dense  castings  free 
from  blisters. 

Under  the  name  "  manganese  steel,"  a  tool-steel  with  the 
normal  content  of  manganese  is  brought  into  commerce. 
Very  likely  it  bears  this  name  only  for  the  purpose  of 
indicating  that  the  steel  has  been  melted  with  a  content 
of  manganese,  and  hence  is  freer  from  pores  and  cracks 
than  other  steel.  Actual  manganese  steel  which  contains  a 
considerable  quantity  of  manganese  (8  to  20  per  cent.)  is 
particularly  strong,  tough,  and  of  such  great  natural  hard- 
ness that  it  can  scarcely  be  worked. 

Such  manganese  steel  is  brought  into  'commerce  in  the 
form  of  finished  tools,  such  as  hatchets,  axes,  etc.,  or  as 
material  for  machine-parts  which  are  to  possess  special 
hardness  and  strength. 

TUNGSTEN. 

Tungsten  is  added  to  tool-steel  if  its  hardness  is  to  be 
essentially  increased  and  its  properties  of  strength  are  to  be 
improved.  Up  to  10  per  cent,  of  tungsten  is  found  in  tool- 


COMPOSITION    OF    TOOL-STEEL.  7 

steel ;  seldom  more,  but  generally  2  to  4  per  cent.,  and 
occasionally — especially  in  English  steel — less  than  1  per 
cent. 

A  larger  content  of  tungsten — over  2  per  cent. — imparts 
to  the  steel,  even  while  in  an  unhardened  condition,  a  fine- 
grained structure  of  characteristic  lustre  Hardened  steel 
alloyed  with  tungsten  shows  even  in  the  presence  of  very 
small  quantities  of  it  a  very  fine  grain  of  dull  lustre.  With 
a  higher  content  of  tungsten  the  structure  becomes  so  fine 
and  velvety  that  the  grain  can  scarcely  be  recognized  with 
the  naked  eye. 

By  a  content  of  tungsten  the  hardness  and  edge-holding 
power  of  the  steel  are  increased,  but  in  a  hardened  state  its 
tenacity  is  decreased.  Hence,  tool-steel  with  a  content  of 
tungsten  is  generally  used  only  for  tools  which  are  to  be 
gently  engaged  and  are  to  possess  great  hardness  and  edge- 
holding  power.  By  repeated  treatment  in  the  fire,  steel 
which  contains  tungsten  or  chromium  loses  its  good  quali- 
ties much  more  rapidly  than  steel  free  from  these  constitu- 
ents, the  edge-holding  power  decreasing  very  rapidly,  while 
brittleness  and  tendency  towards  cracking  in  hardening 
increase.  The  sensitiveness  of  such  steel  towards  over- 
heating is  also  much  greater. 

CHROMIUM. 

Chromium  is  added  to  tool -steel  for  the  same  purpose  as 
tungsten,  but  not  with  the  same  result,  since  it  does  not 
possess  the  same  efficiency  and  makes  the  steel  much  more 
brittle. 

Up  to  3  per  cent,  of  chromium  is  found  in  tool-steel ; 
generally  2.5  per  cent,  in  very  hard  turning  tools,  and 


8  TOOL-STEEL. 

more  seldom  less  than  1  per  cent,  in  softer  steels  (in  some 
English  varieties  of  steel). 

The  property  of  chromium  to  make  steel  especially  resist- 
ant to  blow  and  shock  has  led  to  the  special  use  of  chrome- 
steel  for  shells,  and  in  conjunction  with  nickel,  for  armor 
plates. 

The  appearance  of  the  fracture  of  steel  is  influenced  by  a 
content  of  chromium  in  a  similar  manner  as  by  a  content 
of  tungsten. 

NICKEL. 

Nickel  greatly  improves  the  strength  of  steel,  its  hardness 
and  tenacity  in  an  unhardened  state  being  essentially  in- 
creased. In  a  hardened  state  nickel  does  not  act  in  the 
same  degree  as  tungsten  or  chromium,  so  that  its  use  in 
tool-steel  may  be  left  out  of  consideration  and  nickel-steel 
to  be  employed  in  an  unhardened  state  need  chiefly  be 
mentioned. 

Machine-parts  on  which  heavy  demands  are  made,  and 
which,  either  to  save  weight  or  space,  are  to  have  as  small 
dimensions  as  possible,  or  the  strength  of  which  is  to  be 
especially  increased,  such  as  propeller-shafts,  crank-pins, 
etc.,  are  frequently  constructed  of  nickel-steel,  but  its  great- 
est application  is  for  armor-plate,  cannon,  etc. 

Nickel-steel  as  a  rule  contains  6  to  7  per  cent,  nickel. 
With  a  content  of  over  5  per  cent,  the  steel  possesses  the 
most  favorable  properties  of  strength,  but  is  also  of  such 
natural  hardness  that  it  can  scarcely  be  worked  in  the 
cold  state. 

MOLYBDENUM,  TITANIUM,  VANADIUM. 

Molybdenum  is  seldom  alloyed  with  tool  steel  because 


CLASSIFICATION    OF    TOOL-STEEL. 

the  high  price  of  the  metal  does  not  allow  of  its  extensive 
use,  and  as  its  action  is  very  similar  to  that  of  tungsten  the 
same  result  can  be  attained  with  the  latter  metal. 

Titanium  and  vanadium  are  not  employed  in  the  manu- 
facture of  tool-steel  on  account  of  their  high  price  and  the 
difficulty  in  producing  varieties  of  steel  alloyed  with  them. 

Titanium  and  vanadium  steels  have  been  made  on  a 
small  scale  for  the  purpose  of  testing  their  properties,  and 
titanium  has  been  found  to  impart  special  hardness,  and 
vanadium  special  tenacity,  to  steel. 

Nevertheless  varieties  of  steel — especially  of  English 
origin — are  brought  into  commerce  under  the  names  of 
molybdenum-steel,  titanium-steel,  vanadium-steel,  but  of 
course  they  do  not  contain  any  of  these  constituents. 


II 

CLASSIFICATION  OF  TOOL-STEEL  ACCORDING  TO 
THE  DEGREE  OF  HARDNESS  AND  THE  PUR- 
POSE FOR  WHICH  IT  IS  TO  BE  USED. 

As  regards  the  varieties  of  tool-steel  brought  into  com- 
merce two  groups  may  be  distinguished  so  far  as  products 
of  crucible  steel  are  concerned,  namely  : 

a.  Tool-steel  which  acquires  its  hardness  exclusively  from 

a  content  of  carbon  and  does  not  contain  any  admix- 
tures which  increase  the  hardness. 

b.  Tool-steel,  which  in  addition  to  carbon,  contains  ad- 

mixtures increasing  the  hardness.     In  practice  it  is 
generally  called  special  steel,  or  after  the  kind  of 


10  TOOL-STEEL. 

admixture — chrome-steel,      tungsten-steel,      nickel- 
steel,  etc. 

The  tool-steel  brought  into  commerce  is  nearly  always 
provided  with  the  stamp  of  the  firm  and  a  colored  printed 
label.  The  latter,  in  addition  to  the  name  of  the  firm  and 
trade-mark,  contains  data  regarding  the  degree  of  hardness,, 
the  principal  purposes  for  which  the  steel  is  to  be  used,  and 
the  temperature  to  be  employed  in  forging  and  hardening, 

In  some  manufactories  of  tool-steel  the  degree  of  hardness 
is  expressed  by  figures  corresponding  to  the  content  of  car- 
bon, for  instance,  degree  of  hardness  7 — containing  0.70 
per  cent,  carbon — while  in  others  it  is  expressed  in  such 
allegorical  designations  as :  very  hard,  super-hard,  extra 
hard,  hard-hard,  medium  hard,  tenaciously  hard,  tenacious, 
very  tenacious,  soft.  In  addition  to  these  designations  the 
content  of  carbon  in  per  cent,  is  occasionally  given. 

The  color  of  the  paper  label  is  generally  so  selected  that 
the  hardest  steel  is  provided  with  a  label  of  the  lightest, 
and  the  softest  steel  with  one  of  the  darkest,  color. 

The  varieties  designated  special  steel,  which  as  a  rule  are 
alloyed  with  tungsten  or  chromium,  are  in  practice  pro- 
vided with  labels  of  different  text  and  colors  from  those  of 
ordinary  tool-steel. 

While  the  above-mentioned  allegorical  designations  for 
the  degree  of  hardness  of  tool-steel  are  in  use  in  most  fac- 
tories, not  all  of  them  understand  under  the  same  desig- 
nation the  same  practical  degree  of  hardness  according  to 
the  content  of  carbon.  Thus  one  factory  designates  steel 
with  1.2  per  cent,  of  carbon  as  super-hard,  while  another 
terms  it  medium  hard  or  hard,  and  steel  with  0."6  per  cent, 
carbon  is  designated  as  soft,  tenacious  and  even  tenaciously 
hard. 


CLASSIFICATION    OP    TOOL-STEEL.  11 

Nevertheless  in  practice,  these  designations  serve  their 
purpose,  their  chief  object  being  to  enable  the  consumer 
to  procure  steel  of  the  same  degree  of  hardness  from  the 
same  source  of  supply.  In  judging  the  fitness  of  a  quality 
of  steel  for  a  definite  purpose  the  percentage  of  carbon 
alone  is  by  no  means  decisive. 

It  may  be  accepted  as  a  general  rule  that  for  a  deter- 
mined purpose  a  tool-steel  may  be  selected  which  may  be 
the  harder  (richer  in  carbon),  the  freer  from  injurious  ad- 
mixtures, sulphur,  copper,  phosphorus,  etc.,  it  is. 

The  higher  the  percentage  of  carbon  in  a  steel  which  for 
a  determined  purpose  may  be  chosen,  the  greater  will  be 
the  useful  effect  which  may  be  expected  of  a  tool  made 
therefrom,  but  the  more  care  must  also  be  bestowed  upon 
the  treatment  of  the  tool  while  being  manufactured. 

However,  in  practice,  the  useful  effect  of  the  finished 
tool  is  not  always  taken  as  the  standard  for  judging  the 
fitness  of  a  tool-steel.  In  the  majority  of  cases  steel  is 
judged  according  to  the  manner  in  which  it  can  be  worked 
into  finished  tools  without  making  special  demands  on  the 
intimate  knowledge  and  attention  of  the  tool-smith,  forge- 
man  or  hardener,  and  without  the  requirement  of  special 
devices  for  the  most  important  operations  in  the  manu- 
facture of  tools,  namely,  forging,  annealing,  hardening, 
tempering,  etc. 

Soft  steel  is  less  exposed  to  the  danger  of  over-heating 
and  burning  than  hard  tool-steel,  and  by  reason  of  its 
greater  toughness,  is  less  liable  to  crack  in  hardening. 
Hence  it  requires  less  attention  in  working  and  conse- 
quently is  more  largely  used  in  the  practice  than  hard 
steel.  This  is  one  of  the  reasons  for  the  extensive  employ- 


12 


TOOL-STEEL. 


ment  of  soft  Bessemer  and  Martin  steels  in  the  manufacture 
of  tools,  even  where  the  advantage  of  the  greater  useful 
effect  of  crucible  cast-steel,  which  is  used  much  harder, 
should  be  appreciated.  To  be  sure  this  greater  useful  effect 
is  not  alone  attained  by  the  employment  of  harder  steel, 
very  conscientious  and  careful  work  in  the  manufacture 
of  the  tools  being  also  required,  as  well  as  thoroughly- 
informed  and  experienced  forge-men  and  hardeners. 

From  what  has  been  said  in  the  foregoing,  it  seems  use- 
less to  lay  down  a  rule  which  would  be  even  of  general 
value  for  the  degree  of  hardness  to  be  chosen  for  deter- 
mined purposes.  For  this  reason  the  classification  of  steel 
according  to  the  degree  of  hardness  and  the  purposes  for 
which  it  is  to  be  employed,  as  in  use  in  Bismarckhuette, 
and  which  on  an  average  has  proved  of  practical  value, 
will  here  only  be  given  as  follows : 


Degree  of  hard- 
ness. 

Average 
per  cent, 
of  carbon. 

Purposes  for  which  Employed. 

Very  hard  

1  5 

For  turning  and  planing  knives  drills  turning 

Hard  

1  25 

gravere,  etc.,  for  very  hard  materials. 
For  ordinary  turning  and  planing  knives   rock 

Medium  hard  .... 

Tenaciously  hard  • 
Tough  

1.0 

0.85 
0  75 

drills,  mill  picks,  knife  picks,  scrapers,  etc., 
and  for  cutting  tools  for  hard  metals. 
For    screw-taps,   broaches,    cutters,    tools    for 
stamping  presses  and  for  various  tools  used 
by  locksmiths  and  blacksmiths. 
For    screw-taps,   cutters,    broaches,    matrices, 
swages,  pins,  bearings,  chisels,  gouges,  etc. 
For   chisels  and   gouges    shear-blades    drifts 

goft  

0  fi5 

springs,  hammers,  etc. 

steeling  finer  tools  and  larger  surfaces,  etc. 

SPECIAL    STEELS. 

The  principal  commercial  varieties  of  special  steel,  the 


CLASSIFICATION    OF    TOOL-STEEL.  13 

hardness  of  which  has,  in  addition  to  carbon,  been  in- 
creased by  a  content  of  tungsten  or  chromium,  are  as 
follows : 

Natural  tool-steel,  also   called   self-hardening,  boreas, 

mushet  steel. 
Special  turning  steel. 
Magnet  steel. 

Natural  or  self-hardened  steel  in  an  unhardened  state 
possesses  such  great  cutting  power  and  hardness  that  in 
this  state  it  can  be  employed  for  cutting  tools  which  are 
not  subjected  to  shock. 

When  slowly  cooled  from  a  red  heat  the  hardness  of  nat- 
ural steel  is  greater  than  when  rapidly  cooled  from  this 
temperature,  and  its  behavior  in  hardening  is  thus  the 
reverse  from  ordinary  tool-steel. 

Self-hardened  steel  has  the  advantage  of  retaining  its 
hardness  when  heated,  and  is  therefore  suitable  for  lathe- 
cutters  upon  hard  materials  in  lathes  running  at  high 
speed,  whereby  heat  is  generated,  or  for  taking  off  a  chip 
of  extra  thickness,  etc.  Such  cutters  keep  their  edges  much 
better  than  cutters  of  ordinary  steel.  This  property  of  self- 
hardened  steel  is  due  to  a  higher  content  of  tungsten,  man- 
ganese and  silicon.  The  composition  of  self-hardened  steel 
is  shown  by  the  analyses  given  below  : 

Carbon.  Manganese.  Silicon.  Tungsten. 

English  mushet  steel 1.71  1.8  0.81  7.75 

Styrian  steel 1.78          'l.85  1.01  9.72 

Bismarckhiitte  natural  steel  ...  2.04  1.78  1.08  9.50 

Very  hard  special  turning  steel  contains,  in  addition  to 
1  to  1.5  per  cent,  carbon,  3  to  6  per  cent,  tungsten,  man- 
ganese and  silicon  in  the  usual  quantities  found  in  other 


14  TOOL-STEEL. 

tool-steel.  It  contains  very  seldom  a  higher  percentage 
of  manganese  or  silicon  with  a  smaller  content  of  tungsten, 
as,  for  instance,  the  special  steel  produced  by  Marsh  Bros., 
which  with  only  1.8  per  cent,  of  tungsten  contains  1.8  per 
cent,  of  manganese. 

All  varieties  of  special  steel,  the  hardness  of  which  is 
considerably  increased  by  a  larger  content  of  tungsten,  re- 
quire specially  careful  treatment  in  hardening  if  their 
hardness  is  to  be  thoroughly  effective  without  the  tool 
succumbing  to  the  correspondingly  enormous  hardening 
strains  and  cracking.  To  insure  suitable  treatment  in 
hardening,  such  varieties  of  special  steel  are  generally 
accompanied  by  special,  explicit  instructions. 

Magnet  steel  *  has  a  composition  similar  to  that  of  special 
steel,  and  generally  contains  as  large  a  percentage  of  tung- 
sten, the  latter  exerting  considerable  influence  upon  the 
improvement  of  the  magnetic  properties  of  the  steel. 

Since  the  cutting  power  of  magnet  steel  is  of  secondary 
importance,  it  is  generally  given  such  a  chemical  composi- 
tion as  to  make  its  magnetic  properties  most  effective. 

There  are  numerous  varieties  of  special  steel,  the  chem- 
ical composition  of  which  does  not  differ  from  that  of 
ordinary  steel.  They  are  generally  designated  by  names 
indicative  of  the  purpose  they  are  to  serve,  and  for  which 
they  are  claimed  to  afford  the  greatest  efficiency  attainable. 

Tool-steel  for  definite  purposes,  the  cross  section  of  which 

*It  may  be  accepted  as  a  general  rule  that  the  coercive  power,  i.  e.,  the 
power  with  which  the  magnetism  is  retained,  and  the  quantity  of  magnetism 
taken  up,  are  the  greater  the  harder  the  steel  is.  The  admixtures  of  man- 
ganese and  silicon  in  steel,  which  can  never  be  entirely  avoided,  exert  an  in- 
fluence according  to  the  quantities  present. 


CLASSIFICATION    OF    TOOL-STEEL. 


15 


shows  different  degrees  of  hardness,  is  generally  produced 
by  welding  together  iron  or  mild  steel  with  hard  steel  in 
casting  the  crude  block.  The  accompanying  sketches,  Fig. 
1,  show  such  varieties  of  steel,  the  hatched  lines  represent- 
ing hard  steel. 

FIG.  1. 


Such  steel  is  used  for  a  variety  of  cutting  tools,  the  edges 
of  which  consist  of  hard  steel  and  the  backing  generally  of 
iron ;  further  for  safes,  calks  for  horse  shoes,  etc. 

The  variety  of  tool-steel  brought  into  commerce  under 
the  name  of  soft-centred  or  mild-centred  steel  is  hardest  on 
the  surface,  while  the  interior  is  very  soft.  The  transition 
from  hard  surface  to  soft  interior  is  a  gradual  one  and 
seldom  sharply  defined.  Such  steel  is  produced  by  cemen- 
tation of  mild  steel,  carbonization  being  arrested  at  a 
definite  stage.  This  mode  of  production  frequently  results 
in  an  unequal  material,  and  for  this  reason  such  steel  is 
seldom  used  in  practice  for  the  manufacture  of  tools.  It 
is,  however,  employed  to  advantage  for  machine-parts  which 
have  to  be  very  tough,  but  portions  of  the  surfaces  of  which 
have  to  be  harder  to  protect  them  against  rapid  wear,  for 
instance,  crank  pins,  dynamo  shafts,  etc.,  the  bearing  por- 
tions of  which  are  hardened  while  their  interior  are  left 
tough  and  soft. 


16  TOOL-STEEL. 

III. 

OBSERVATIONS    ON    THE    EXTERNAL    APPEAR- 
ANCE OF  COMMERCIAL  TOOL-STEEL. 

WHEN  receiving  tool -steel,  the  eye  of  the  consumer  is 
involuntarily  drawn  towards  its  external  condition.  So  far 
as  the  quality  of  the  steel  is  concerned,  the  most  percept- 
ible features  in  this  respect  are  the  appearance  of  the 
fracture  and  the  cleanness  of  the  surface. 

With  steel  carefully  made  defects  can  seldom  be  noticed 
by  the  fracture  and  surface. 

The  surface  of  steel  may  show  the  following  defects : 

Scales,  the  form  of  which  represents  a  single  line  running 
in  a  curve,  or  the  line  may  consist  of  several  coherent 
curves.  Such  scales  generally  originate  from  dross  on  the 
surface  of  the  block  which  has  not  been  removed,  from 
remnants  of  slag  or  from  skins  formed  in  casting  the  steel. 
They  are  more  seldom  due  to  faults  in  forging  or  rolling. 

Cracks  are  outlined  on  the  surface  of  the  steel  by  short 
lines,  either  singly  or  in  groups,  running  parallel  to  the 
longitude  of  the  surface.  They  are  partially  concealed 
from  view  by  the  layer  of  oxide  covering  the  steel,  but  may 
readily  be  exposed  by  means  of  a  file.  These  cracks  are 
due  to  pores  which  in  casting  the  steel-ingot  have  been 
formed  immediately  below  the  surface. 

Seams  are  formed  by  the  steel  protruding  laterally  in 
rolling  or  forging  in  the  swage  and  by  turning  down  and 
squeezing  in  the  protruded  material  in  the  further  working 
of  it.  The  seams  run  always  parallel  to  the  longitude  of 


EXTERNAL  APPEARANCE  OF  COMMERCIAL  TOOL-STEEL.       17 

the  steel,  generally  on  two  sides  or  edges  of  it ;  more  seldom 
alternately,  or  on  one  side  only.  On  rolled  steel  such 
seams  readily  escape  observation  when  they  are  covered 
with  a  layer  of  oxide. 

Edge-cracks  are  cross-rents  on  the  edges  which  run  ver- 
tically to  the  direction  of  the  length  of  the  steel.  They  in- 
dicate red-shortness  or  hot-shortness,  or  that  the  steel  in 
forging  has  been  strongly  overheated  (burnt).  Such  steel 
is  of  course  entirely  unfit  for  the  manufacture  of  tools. 

In  the  further  working  of  the  steel  the  principal  defects 
noticeable  on  the  surface,  which  have  been  mentioned 
above,  are  frequently  productive  of  defective  tools  because 
cracks  formed  in  hardening  originate  from  them. 

The  appearance  of  the  fracture  is  not  decisive  as  regards 
the  quality  of  unhardened  steel,  and  only  within  very  un- 
certain limits  as  regards  its  hardness. 

The  structure  of  soft  steel  shows  a  coarse  grain,  and  that 
of  hard  steel  generally  a  fine  grain,  the  latter  being  the 
finer  the  more  carbon  the  steel  contains,  provided  the  sur- 
faces of  the  fractures  which  are  to  be  compared  have  been 
produced  under  the  same  conditions. 

If  the  fracture  of  very  soft  steel  shows  a  proportionately 
coarse-grained  structure  and  at  the  same  time  a  dark  streak 
towards  the  edge  in  which  an  actual  grain  can  no  longer 
be  recognized,  but  an  almost  fibrous  structure,  it  is  indica- 
tive of  very  soft  steel  with  a  very  small  content  of  carbon 
— below  0.6  per  cent.,  with  less  than  0.3  per  cent,  manga- 
nese. 

If  a  dark,  lustreless  streak  is  noticeable  on  the  fracture  of 
hard  steel  which  otherwise  shows  a  fine-grained  structure, 
it  is  indicative  of  the  presence  of  carbon  in  graphitic  form. 
2 


18  TOOL-STEEL. 

Such  steel  acquires  only  an  unequal,  insufficient  degree  of 
hardness  and  always  yields  bad  tools. 

The  following  defects,  if  present,  may  be  observed  on  the 
surfaces  of  the  fractures  of  tool-steel  : 

1.  Flaws   or    blisters,   in   the  center,   and    more   seldom, 

towards  the  edge  of  the  steel. 

When  towards  the  edge  of  the  steel,  they  are  due 
to  pores,  and  when  in  the  centre  of  the  fracture,  to 
the  pipe. 

2.  A  spot,  generally  symmetrically  formed,  in  the  centre 

of  the  steel,  which  shows  a  coarser  or  finer  structure 
than  the  surrounding  parts.  Such  spots  are  formed 
by  liquation  on  cooling  steel  freshly  cast,  and  their 
chemical  composition  differs  from  that  of  the  sur- 
rounding portions.  When  the  fracture  of  such  steel 
is  filed,  ground,  polished  and  pickled  in  acid,  spots 
of  unequal  hardness  (unequal  chemical  composition) 
are  outlined  as  quite  sharply  defined  surfaces  of 
different  coloration. 

3.  When  cutting  up  a  bar  of  steel  into  the  separate  parts 

serving  for  the  manufacture  of  a  tool,  flaws  may 
also  be  noticed  in  the  centre  of  the  steel.  Such 
flaws  are  only  in  rare  cases  attributable  to  a  con- 
tinuation of  the  pipe,  but  are  more  frequently  due 
to  destructive  forging.  In  forging  bar-steel  it  is 
nearly  always  worked  colder  in  the  centre  than 
on  the  ends,  the  interior  being  readily  shattered 
thereby.  The  flaws  thus  formed  seldom  extend  to 
the  surface  of  the  steel,  and,  therefore,  escape  detec- 
tion in  the  works  where  the  steel  is  produced.  The 
defect  caused  by  destructive  forging  is  more  fre- 


FRACTURE    OF    STEEL.  19 

quently    found   in   hard    steel    and    in  material   of 
small  or  thin  dimensions. 

In  most  tool-steel  works  it  is  sought  to  avoid  the  above- 
mentioned  defects  which  can  be  noticed  on  the  surface  and 
fracture  of  the  steel,  and  the  various  products  are  subjected 
to  very  careful  inspection  before  being  shipped  to  prevent 
defective  material  from  reaching  the  consumer. 


IV. 

OBSERVATIONS  ON   THE   FRACTURE  OF  STEEL, 
WITH  REGARD  TO  THE  STRUCTURE  IN 
THE    HARDENED  AND   NON- 
HARDENED  STATES. 

IT  requires  considerable  practice  and  much  experience  to 
be  able  to  judge,  with  any  degree  of  certainty,  from  the 
appearance  of  an  otherwise  faultless  fracture,  the  quality 
and  incidentally  the  hardness  of  a  variety  of  steel. 

As  previously  mentioned,  the  structure  of  steel  becomes 
more  fine-grained  as  the  hardness  increases.  However, 
steel  of  the  same  degree  of  hardness  may  show  an  entirely 
different  structure  if  before  being  broken  it  has  been 
worked  in  different  ways,  and  after  having  been  worked, 
has  been  cooled  from  high  temperatures  of  different  de- 
grees. 

Tool-steel  which  has  been  heated  and  then  very  slowly 
cooled,  and  the  fracture  of  which  has  been  effected  by 
nicking  and  breaking  while  in  the  cold  state,  shows  the 
most  coarse-grained  structure  pertaining  to  its  degree  of 
hardness. 


20  TOOL-STEEL. 

The  appearance  of  the  fracture  of  unhardened  steel  as 
brought  into  commerce  is  in  the  main  dependent  on  the 
following  conditions : 

1.  On  the  temperature  from  which  the  steel   has  been 
cooled  before  it  is  broken. 

Changes  in  shape  are  much  more  rapidly  effected 
by  rolling  than  by  forging,  and  the  steel,  when 
allowed  to  cool,  has  a  much  higher  temperature. 
For  this  reason  rolled  steel  has,  as  a  rule,  a  more 
coarse-grained  structure  than  forged  steel. 

The  fractures  of  the  two  ends  of  the  same  bar 
of  forged  steel  show  sometimes  a  different  appear- 
ance if,  after  forging,  one-half  of  the  bar  has  been 
cooled  from  a  lower  or  higher  temperature  than  the 
other. 

2.  On  the  degree  of  mechanical  manipulation. 

Tool-steel  of  the  same  degree  of  hardness  shows  a 
finer  structure  in  smaller  dimensions  and  a  coarser 
structure  in  larger  dimensions, 

In  producing  smaller  dimensions  the  loss  of  heat 
takes  place  more  rapidly,  but  the  change  in  shape 
requires  more  powerful  working  of  the  steel ;  and 
this  being  finally  effected  at  a  lower  temperature, 
the  fracture  shows  a  fine-grained  structure. 

3.  On  the  temperature  of  the  steel  before  it  is  worked. 

Steel  over-heated  in  heating  for  forging  or  rolling 
acquires  an  entirely  or  partially  coarse-grained 
structure,  which  possesses  a  characteristic  bright 
lustre  different  from  the  normal  color  of  steel. 

This  structure  frequently  forms  a  border  around 
the  edge  of  the  fracture  or  runs  from  the  edge 


FRACTURE    OF    STEEL.  21 

towards  the  centre  of  the  steel ;  and  if  the  steel  had 
been  over-heated  to  a  higher  degree,  does  not  en- 
tirely disappear  by  subsequent  manipulation. 
4.  On  the  manner  in  which  fracture  has  been  effected. 

Steel  which  has  been  nicked  in  the  cold  state  and 
then  broken  shows  a  more  coarse-grained  structure 
than  steel  which  has  been  nicked  in  a  red-hot  state 
and  broken  after  cooling. 

Nicking  in  a  red-hot  state  is  equivalent  to  a 
mechanical  manipulation  at  a  lower  temperature, 
and  hence  the  finer  structure. 

The  appearance  of  the  fracture  of  hardened  steel  is  de- 
pendent on  the  following  conditions  : 

1.  On   the  temperature  at  which  the  steel   by  rapid 
cooling  has  been  hardened. 

Suppose  a  bar  of  steel  has  been  heated  so  that  the 
brightest  white  heat  slowly  extends  from  one  end  to 
the  other,  passing  through  a  yellow,  red,  and  brown 
heat  to  hand-warm.  Now,  if  this  bar  is  hardened 
by  being  quickly  quenched  in  water,  the  changes  in 
the  structure  of  the  steel  while  being  heated  and  the 
influence  of  the  various  degrees  of  heating  upon  the 
structure,  the  degree  of  hardness  and  the  toughness, 
may  be  recognized  by  the  separate  broken  portions 
and  the  appearance  of  their  fractures. 

The  higher  the  temperature  at  which  hardening 
has  been  effected,  the  more  coarse-grained  the  struc- 
ture of  hardened  steel  will  be. 

The  accompanying  tables  show  the  influence 
of  the  various  degrees  of  temperature  upon  hard- 
ened and  unhardened  steel,  and  their  general  appli- 
cation in  practice. 


22  TOOL-STEEL. 

2.  On  the  dimensions  of  hardened  steel  Steel  with  a 
small  cross-section  yields  up  heat  more  quickly  in 
hardening  than  steel  with  a  large  cross-section.  It 
is  more  uniformly  hardened  throughout,  and  its 
fracture  shows  a  more  uniformly  fine-grained  struc- 
ture. 

Steel  of  larger  dimensions  yields  up  its  interior 
heat  but  slowly,  and  hence  does  not  acquire  the 
same  degree  of  hardness  in  the  interior  as  towards 
the  surface.  The  face  of  the  fracture  shows  in  the 
centre  a  more  coarse-grained  structure  which  be- 
comes more  fine-grained  towards  the  edges. 
3.  The  appearance  of  the  fracture  in  the  hardened  state 
is  dependent  on  the  structure  only  when  the  steel 
has  been  overheated  or  when  it  has  previously  been 
subjected  to  vigorous  mechanical  manipulation.  In 
the  former  case  the  steel  in  the  hardened  state  shows 
a  coarser,  and  in  the  latter  case,  an  especially  fine, 
structure. 


V. 

PRACTICE  OF  THE  FIRE-TREATMENT  OF  STEEL. 

IN  the  manufacture  of  tools  repeated  heating  of  the  steel 
is  in  most  cases  required,  partially  for  the  purpose  of  shap- 
ing (forging),  partially  for  increasing  the  capacity  of  being 
worked  (annealing),  and  for  hardening  and  tempering  the 
finished  tool. 

Shaping  can  only  in  a  few  cases  be  effected  by  one  heat- 


FIRE-TREATMENT    OF    STEEL.  23 

ing,  and  in  many  cases  a  worn-out  tool  has  repeatedly  to 
pass  through  the  above-mentioned  operations  without  its 
quality  suffering  injury  from  repeated  heating. 

Hence,  in  the  manufacture  of  tools  particular  attention 
has  to  be  paid  to  every  operation  for  which  the  steel  has  to 
be  heated,  and  the  appliances  for  this  purpose  should  be 
properly  adapted. 

This  adaptation  should  be  in  accordance  with  the  follow- 
ing principles,  which  must  be  strictly  observed : 

1.  The  steel  should  always  be  heated  so  uniformly  that 

it  is  not  heated  more,  either  in  its  entirety  or  par- 
tially, than  is  absolutely  necessary  for  the  subse- 
quent operation. 

2.  Heating  should    be    effected    as    rapidly    as   possible 

without  bringing  the  single  parts  (corners,  edges) 
of  the  steel  to  a  higher  heat  prior  to  the  body. 

Though  simple  and  self-evident  as  these  principles  may 
appear,  they  are  frequently  transgressed  as  regards  the 
operation  in  question  itself,  as  well  as  in  the  appliances  for 
carrying  it  out. 

The  appliances  for  heating  the  steel  include  in  the  main 
fire  and  furnaces,  as  well  as  fuel. 

The  quantities  of  fuel  and  their  value  are  mostly  small 
in  comparison  with  the  value  of  the  tool  to  be  produced, 
and  the  essentially  greater  efficiency  of  a  tool  which  has 
been  carefully  made. 

The  choice  of  fuel  depends  partially  on  local  conditions 
arid  partially  on  the  manner  in  which  it  is  to  be  applied. 
In  many  cases  the  heating  devices  are  adapted  to  the  pur- 
pose in  view  as  well  as  to  the  fuel  at  disposal. 

The  disadvantages  which  may  result,  as  far  as  the  qual- 


24  TOOL-STEEL. 

ity  of  the  steel  is  concerned,  from  the  use  of  certain  fuels 
will  now  be  described,  as  well  as  the  means  necessary  to 
successfully  avoid  them. 

Hard  coke,  which  does  not  stain  the  hand,  and  when 
struck  emits  a  clear  sound,  is  used  in  the  manufacture 
of  tools  in  the  open  fire  as  well  as  in  furnaces.  The  harder 
the  coke  is,  the  higher  the  temperature  will  be,  and  the 
more  air  for  the  combustion  of  the  coke  required. 

Hence,  in  a  coke-fire,  tool-steel  is  readily  heated  too 
rapidly  and  too  much,  and  the  larger  the  pieces  of  coke 
the  more  it  is  exposed  to  the  action  of  the  blast.  These 
are  conditions  under  which  the  steel  may  readily  become 
overheated,  and  even  burned. 

When  no  other  fuel  besides  hard  coke  is  available,  the 
furnace  shown  in  Fig.  2  should  be  used  for  heating  the  steel. 

For  the  construction  of  this  furnace  take  a  piece  of  fire- 
tube,  or  similar  material,  about  3J  feet  long  and  16  to  24 
inches  in  diameter,  and  provide  it  at  a,  b,  c  with  apertures 
to  which  doors  of  stout  sheet  iron  are  fitted.  Place  the 
tube  thus  prepared  upon  an  ordinary  brick  pavement,  line 
it  with  fire-brick,  as  shown  in  the  illustration,  fix  the  blast- 
pipe  w  under  the  grate,  and  close  the  upper  portion  of  the 
brick  work  with  an  arch.  The  cover  of  the  furnace  is  pro- 
vided with  an  aperture  4|  to  6  inches  in  diameter,  in 
which  is  fitted  a  smoke-pipe  3J  to  13  feet  high  and  pro- 
vided with  a  damper  for  regulating  the  draught. 

The  fuel  is  introduced  through  the  doors  a,  6.  The  door 
6  is  the  actual  working  door,  the  door  a  serving  for  passing 
through  long  bars,  which  are  to  be  heated  in  the  centre  for 
the  purpose  of  dividing  them. 

The  coke  burning  in  the  space  8  heats  the  working  space 


FIRE-TREATMENT    OF    STEEL. 


25 


A,  in  which  the  tool,  held  by  means  of  tongs  or  resting 
upon  a  grate-like  support,  is  heated.  With  a  smoke-pipe 
of  sufficient  height,  a  blast-pipe  is  not  actually  required, 
since  the  free  draught  is  sufficient  to  produce  the  high  and 


uniform  heat  required  in  A.  The  suitable  degree  of  tem- 
perature can,  within  a  certain  limit,  be  effected  by  regulat- 
ing the  draught. 

Smith-coal  or  forge-coal  The  variety  of  coal  thus  desig- 
nated cakes  readily,  swelling  up  thereby,  and  is  most 
frequently  used  for  open  forge-fires.  However,  it  contains 


26  TOOL-STEEL. 

sometimes  a  high  percentage  of  sulphur,  the  presence  of 
which  may  spoil  tool-steel  heated  in  such  fire.  To  remove 
a  content  of  sulphur,  allow  the  coal  to  burn  thoroughly 
through  until  no  more  smoke  is  evolved,  repeating  the 
operation  every  time  fresh  fuel  is  added. 

The  effect  produced  by  a  content  of  sulphur  in  the  coal 
upon  the  steel  heated  therein  is  as  follows : 

At  a  high  temperature  sulphur  has  a  great  tendency 
towards  combining  with  iron.  This  combination  cannot 
be  hardened  and  causes  the  formation  of  so-called  soft  spots 
in  the  steel,  i.  e.,  spots  of  greater  or  smaller  extent  on  the 
surface  of  the  steel,  which  acquire  no  hardness  whatever  in 
hardening  the  tool. 

When  smith-coal  in  an  open  fire  is  ignited  it  readily 
cakes  on  the  surface  to  a  coherent  cover  underneath  which 
combustion  takes  place  at  a  very  high  temperature.  If 
this  cover  is  not  broken  up  such  fire  may  burn  "hollow." 
If  steel  for  the  purpose  of  heating  is  brought  into  the 
hollow  space,  it  is  heated  in  immediate  contact  with  the 
blast  and  is  "  burnt "  at  a  temperature  which,  with  the 
exclusion  of  the  oxygen  of  the  air,  would  not  be  high 
enough  to  spoil  it.  In  heating  tool-steel  in  an  open  fire  it 
is,  therefore,  necessary  to  prevent  the  coal  from  forming  a 
solid  cover.  The  development  of  a  less  intense  heat  in  a 
fire  frequently  loosened  is  rather  an  advantage  in  heating 
steel. 

Coke  dust.  Coke  in  minute  fragments  or  reduced  to  dust 
is  not  suitable  for  use  in  an  open  fire,  because  the  blast 
cannot  with  sufficient  ease  penetrate  between  the  inter- 
spaces of  the  fuel  to  induce  sufficiently  extensive  combus- 
tion. Such  coke  may  be  used  mixed  with  smith-coal,  it 
readily  caking  together  with  it. 


FIRE-TREATMENT    OF    STEEL.  27 

The  highest  degree  of  heat  developed  in  an  open  fire 
is  immediately  in  front  of  the  tuyere,  and  in  the  zone  sur- 
rounding it,  within  which  the  blast,  scattered  by  striking 
the  coal  and  weakened  in  force,  just  maintains  the  coal  in 
full  glow,  is  found  the  degree  of  heat  required  for  forging 
and  hardening.  This  heat,  however,  decreases  too  rapidly 
in  intensity  towards  the  surface  of  the  fuel  put  on. 

The  heat  developed  in  the  middle  zone  is,  of  course, 
not  uniform,  it  being  more  intense  towards  the  centre  of 
the  fire  and  less  so  towards  the  surface.  For  this  reason  it 
will  be  difficult  to  heat  articles  to  a  uniform  heat  in  this 
zone  when  it  is  narrow,  -/.  e.,  when  but  a  small  quantity  of 
fuel  has  been  put  on.  The  more  fuel  is  put  on,  the  greater 
will  be  the  width  of  the  heating  zone  which  can  be 
utilized  for  forging  and  hardening,  and  the  larger  in  size 
the  articles  may  be  which  can  be  heated  in  it.  It  is 
extremely  difficult  to  heat  in  an  open  fire  to  a  uniform 
temperature  pieces  of  especially  large  size,  such  as  anvils, 
hammer-blocks,  swages,  etc.,  it  being  almost  impossible  to 
avoid  roasting  the  steel  for  several  hours.  Generally  it  is 
also  partially  over-heated,  while  some  portions  are  insuf- 
ficiently heated.  In  such  cases  the  operation  may  be 
essentially  facilitated  by  allowing  the  blast  to  enter 
through  two  tuyeres  arranged  parallel  at  a  distance  of 
80  to  200  inches  from  each  other.  The  tool  imbedded  in 
the  space  between  the  nozzles  then  receives  an  adequate 
supply  of  heat,  and  needs  to  be  turned  less  frequently. 

When  long,  thin  articles,  for  instance  screw-augers, 
broaches,  shear  blades,  cutters,  etc.,  are  to  be  heated  to  a 
uniform  temperature,  even  skilled  forgemen  encounter 
many  difficulties  on  account  of  the  heat  not  being  uni- 


28 


TOOL-STEEL. 


formly  distributed  in  the  open  fire.  The  corners  and  edges 
of  the  tool  are  readily  over  heated,  and  subsequently  in 
hardening  break  off.  The  tool,  as  a  rule,  is  also  not  uni- 
formly heated,  one  end  or  the  centre  showing  a  somewhat 


brighter  heat  than  the  other  portions.  In  this  case  the 
open  fire  can,  with  small  expense,  be  readily  converted  into 
a  provisional  furnace  as  shown  in  Figs.  3  and  4. 

Set  up  bricks,  in  the  manner  shown  in  the  illustration 


FIG.  4. 


(Fig.  3),  around  the  blast  aperture  so  that  an  opening  is 
left  at  m  for  loosening  the  fuel  K.  By  laying  a  flat  piece  of 
iron  across,  an  aperture  is  made  at  A,  and  after  putting  on 


FIRE-TREATMENT    OF    STEEL.  29 

the  fuel,  the  structure  is  closed  with  a  sheet-iron  cover, 
which  may  be  provided  with  a  piece  of  stove-pipe  for  a 
chimney.  By  placing  a  few  iron  rods  in  the  working  aper- 
ture A,  a  grate  may  be  made  upon  which  the  steel  is  heated 
without  coming  in  contact  with  the  fuel.  During  the  pro- 
cess of  heating,  the  aperture  A  is  to  be  closed  by  a  strip  of 
sheet-iron  placed  upon  the  somewhat  projecting  grate-bars. 
In  a  provisional  furnace  thus  arranged,  thin,  long  tools 
are  readily  and  well  heated  to  a.  uniform  temperature, 
especially  with  the  use  of  charcoal  as  fuel. 

For  longer  articles  it  will  be  necessary  to  arrange  inside 
the  heating  space  two  tuyeres  alongside  each  other  and 
brick  them  over. 

Unequal  heating  or  over-heating  of  some  teeth  is  an 
especially  disagreeable  feature  in  heating  cutters,  and  can- 
not always  be  prevented  even  with  the  greatest  care. 
However,  large  cutters  are  scarcely  ever  hardened  from  an 
open  fire,  and  when  it  is  done  it  is  at  the  risk  of  the  expen- 
sive tool. 

Small  cutters,  punches,  etc.,  as  well  as  small  tools  in 
general,  which  are  to  be  hardened  all  over,  can  be  safely 
heated  in  a  muffle  built  in  the  open  fire  as  shown  in 
Fig.  4. 

Construct  from  old  sheet-iron  a  pot  of  a  size  adapted  to 
the  articles  to  be  heated  and  line  it  with  clay  mixed  with 
cow-hair.  Build  up  bricks  around  the  tuyere  and  arrange 
the  muffle  as  shown  in  Fig.  4.  The  back  portion  of  the 
muffle  is  placed  upon  a  piece  of  iron  coated  with  clay 
which  rests  upon  the  bricks  or  upon  a  piece  of  brick  cut  so 
that  the  blast  is  divided  or  diverted  into  two  lateral 
currents. 


30  TOOL-STEEL. 

The  mouth  of  the  muffle  is  closed  by  a  piece  of  sheet-iron 
b  and  the  top  of  the  furnace  by  a  sheet-iron  plate  d. 

It  is  of  great  advantage  if  the  muffle  M  can  be  fixed  be- 
tween two  tuyeres.  The  fuel  is  introduced  from  the  top, 
the  cover  d  being  removed  for  that  purpose.  An  aperture 
for  loosening  the  fire  is  provided  on  the  side.  Of  course 
the  articles  to  be  heated  must  not  be  brought  into  the 
muffle  before  the  interior  of  the  latter  has  acquired  a  suit- 
able uniform  temperature. 

The  devices  for  open  fires  shown  in  Figs.  3  and  4  are 
practicable  with  coke  or  charcoal,  but  not  with  coal.  If 
coal  has  to  be  used,  one  of  the  reverberatory  furnaces  to  be 
described  later  on  may  be  employed  for  uniformly  heating 
large  pieces  of  steel  or  tools  made  therefrom. 

Mild  soft  coke,  such  as  is  formed  on  the  grate  by  the 
combustion  of  caking  coal,  gas-house  coke  in  small  pieces, 
etc.,  which  are  of  a  dark  color,  stain  the  hand,  crumble 
readily,  and  when  struck  do  not  emit  a  clear  sound,  are  not 
suitable  for  forging  and  hardening  from  open  fires.  Tools 
which  come  only  partially  in  contact  with  the  fire  and  the 
manufacture  of  which  is  simple  and  rapidly  effected,  such 
as  hand  and  cross-cut  chisels,  pointed  chisels,  drills,  ham- 
mers, etc.,  can,  without  hesitation,  be  forged  and  hardened 
from  open  fires  with  such  coke.  However,  for  all  open 
fires,  charcoal  is  without  doubt  the  most  suitable  fuel.  It 
readily  yields  to  a  greater  extent  the  required  degrees  of 
temperature  without  a  more  abundant  application  of  blast, 
and  never  contains  foreign  admixtures  injurious  to  tool- 
steel.  Hence  charcoal  should  be  exclusively  used  as  fuel 
when  tools  of  a  finer  quality  are  to  be  forged  or  hardened 
from  an  open  fire,  or  when  steel  of  special  hardness,  and 


FIRE-TREATMENT    OF    STEEL.  31 

hence  more  sensitive  to  fire,  is  to  be  subjected  to  these 
operations. 

The  great  advantage  of  the  use  of  charcoal  for  open  fires 
is  due  to  its  purity  and  ready  combustibility,  and  further 
to  the  fact  that  the  degrees  of  temperature  developed  in  the 
fire  can  be  more  readily  observed  from  the  exterior  than 
with  the  use  of  any  other  fuel. 

The  great  combustibility  of  charcoal  allows  of  the  use 
of  the  smallest  quantities  of  blast,  and  hence  greater  protec- 
tion against  injurious  effects  to  the  steel  is  afforded.  The 
action  of  the  blast  upon  tool-steel  or  the  finished  tool  pro- 
duced from  it,  is  the  more  injurious  the  higher  the  tem- 
perature at  which  it  takes  place,  and  the  longer  it  lasts. 

The  disadvantages  resulting  from  such  action  may  be 
stated  as  follows : 

1.  The   steel    oxidizes  on  the   surface   and   sinter  is 
formed,  and  where  oxidation  has  penetrated  more 
deeply  uneven  spots  result,  so  that  the  steel,  espec- 
ially in  finished  tools,  presents  a  bad   appearance, 
the  smooth  surface  having  been  destroyed. 

2.  The  oxygen  of  the  blast  readily  withdraws  from  the 
surface  of  the  hot  steel,  especially  on  the  edges  and 
corners,  a  portion   of  the   carbon,   the  steel  losing 
thereby  considerably  in  hardness  and  cutting  power. 

3.  When  the  temperature  produced  in  the  open  fire  is 
high  and  a  great  quantity  of  blast  is  present,  the 
oxygen  of  the  latter  may  not  only  combine  with  the 
iron  and  carbon  on  the  surface  of  the  steel,  but  may 
also  penetrate  more  deeply  into  the  latter,  and  by 
forming  oxides  with  the  iron,  manganese  and  silicon 
of  the  steel  cause  a  severance  of  the  structure  of  the 


32  TOOL-STEEL. 

latter.  Such  steel  is  burnt  and  shows  on  the  edges 
cracks  of  various  depths. 

In  the  subsequent  forging,  such  steel  crumbles  on  the 
places  where  the  cracks  are,  and  also  in  hardening  the  steel 
cracks.  There  is  no  way  of  protecting  the  steel  from  the 
action  of  the  blast  in  an  open  fire.  Such  protection  must 
be  given  by  the  mode  of  working,  which  should  be  as  de- 
scribed below  : 

Heat  the  cold  tool-steel  or  the  finished  tool  by  placing  it 
upon  the  surface  of  the  fuel,  turning  it  frequently,  and 
then  push  it  into  the  portion  of  the  fire  showing  the  lowest 
degree  of  heat,  hence  near  the  circumference.  Allow  the 
steel  to  remain  here  until  it  shows  a  uniform  dark-red  heat, 
and  then  push  it  into  the  hotter  zone  towards  the  centre 
of  the  fire.  To  be  sure,  in  this  place  the  blast  strikes  the 
steel,  but  the  latter  having  been  preparatively  heated,  the 
action  of  the  blast  produces  but  little  effect,  except  when 
the  pieces  are  of  such  large  dimensions  as  to  prevent  rapid 
heating. 

If  the  effect  of  the  blast  is  to  be  weakened,  the  current  of 
air  is  reduced  by  placing  in  front  of  the  nozzle  irregularly- 
formed  fragments  of  fire-brick,  or  the  steel  is  protected  by 
pieces  of  sheet  iron  arranged  between  the  nozzle  and  the 
steel.  In  the  latter  case  it  is  necessary  first  to  put  on  a 
large  quantity  of  fuel  and  bring  it  into  a  red  heat.  The 
attacks  of  the  air  upon  the  surface  of  the  steel  may  be 
lessened  by  dipping  the  steel  before  heating  in  milk  of 
lime  or  clay  water  (1  Ib.  of  clay  to  1  quart  of  water  thor- 
oughly stirred  together). 

Although  open  fires  are  much  used  and  are  very  con- 
venient for  most  purposes  in  the  manufacture  of  tools,  their 


FIRE-TREATMENT    OF    STEEL.  33 

disadvantages  make  themselves  very  much  felt  in  the  pro- 
duction and  hardening  of  large  complicated  tools,  and  in  the 
manufacture  of  implements  in  large  quantities. 

When  a  large  number  of  tools,  for  instance,  chisels, 
drills,  picks,  etc.,  are  to  be  made  or  to  be  repaired,  a  dozen 
of  them  are  at  one  time  put  in  the  fire  with  the  intention 
of  preparatively  heating  them,  but  the  result  is  that  they 
are  not  uniformly  heated,  they  being  partially  overheated 
and  even  burnt.  Such  tools  will  in  use  prove  not  uniform 
and  in  consequence  there  will  be  loss  of  steel,  as  well  as 
but  slight  efficiency. 

Hence  in  factories  where  these  causes  have  been  recog- 
nized, it  has,  as  a  rule,  been  endeavored  to  arrange  the 
heating  devices  so  that  the  defects  and  imperfections 
due  to  the  heating  of  the  steel  are  in  the  main  avoided. 
By  such  devices  the  strain  on  the  tool-smith  is  relieved  and 
limited  to  what  is  most  essential,  and  fewer  demands  are 
made  on  his  skill.  Beside,  as  has  been  frequently  men- 
tioned, the  efficiency  of  a  tool  carefully  made  is  greater 
and  consequently  there  is  a  saving  in  material  and  wages. 
The  greater  expense  caused  by  the  selection  of  better  de- 
vices for  forging  and  hardening  are  rapidly  and  fully  made 
up  by  what  is  saved  in  wages. 

Before  entering  into  a  discussion  of  the  furnaces  or  fires 
to  be  used  in  separate  cases,  the  great  importance,  especi- 
ally in  hardening,  of  the  influence  of  light  in  judging  the 
degree  of  temperature  of  the  steel  may  here  be  referred  to. 

If  a  bar  of  steel,  such  as  has  been  described  on  p.  21,  be 

heated,  the  degrees  of  heat  mentioned  in  the  table  facing 

p.  21  can  be  observed  on  it.     These  observations  are  based 

upon  the  purely  subjective  perception  of  the  observer,  ac- 

3 


34  TOOL-STEEL. 

cording  to  the  relation  between  the  heat  and  surrounding 
light.  The  heat  of  the  same  bar  of  steel  will  in  absolute 
darkness  present  a  different  picture  from  that  in  dispersed 
day-light  or  in  bright  sunshine.  What  in  the  first  case 
seemed  to  be  bright  red,  appears  cherry-red  in  the  second 
case,  and  dark  red  in  sunshine.  By  a  changing  light  the 
eye  is  dazzled  and  becomes  uncertain  in  judging  the  de- 
grees of  temperature. 

By  bearing  in  mind  that  the  degrees  of  temperature  to 
be  used  in  forging,  and  especially  in  hardening,  lie  within 
very  narrow  limits  and  must  be  exclusively  measured  by 
the  eye  of  the  forge-man  or  hardener,  it  will  be  readily 
understood  that  not  too  much  should  be  expected  from 
these  artisans  if  forced  to  work  in  a  light  room  or  in  a 
much  changing  light.  The  advantage  afforded  to  the 
workmen  in  this  respect  is  to  the  interest  of  the  consumer 
of  the  tools  made  by  them. 

Such  advantage  can  readily  be  afforded  by  locating  the 
devices  for  forging  and  hardening  tools  in  the  portion  of 
the  works  which,  for  want  of  light,  are  not  suitable  for 
other  purposes,  or  if  this  cannot  be  done,  to  prevent  the 
entrance  of  a  bright  and  changing  light  through  the 
windows  by  providing  them  with  a  coat  of  paint,  or 
curtains,  etc. 

As  previously  mentioned,  heating  the  steel  in  an  open 
fire  has  many  drawbacks,  which  mainly  result  from  the 
uneven  temperature  produced,  the  direct  contact  of  the 
steel  with  the  fuel,  and  from  the  blast.  To  avoid  these 
drawbacks  or  to  weaken  their  effect,  furnaces  are  constructed 
in  which  the  steel  can  come  in  contact  only  with  the  heated 
combustion-gases  of  the  fuel,  but  not  with  the  fuel  itself  or 
the  blast. 


FIRE-TREATMENT    OF    STEEL.  35 

As  regards  their  arrangement,  the  different  kinds  of 
furnaces  are  constructed  alike  and  are  chiefly  intended  for 
fuels  yielding  no  actual  flame.  The  furnace  previously 
described  and  illustrated  (Fig.  2)  is  the  most  simple  type. 

The  low  degree  of  temperature  which  must  be  produced 
in  such  furnaces  for  heating  tool-steel  allows  in  most  cases 
of  their  being  kept  in  operation  without  the  use  of  blast  if 
a  chimney  of  sufficient  height — 10  to  13  feet — is  provided. 
One  chimney  may  be  used  in  common  for  several  furnaces. 

The  dimensions  of  the  furnaces  described  below  are  calcu- 
lated for  heating  articles  of  medium  size.  They  may  be 
built  larger  or  smaller  according  to  the  purpose  they  are  to 
serve,  and  the  dimensions  must  then  be  determined  in  pro- 
portion to  the  measurements  given  in  the  illustrations.* 

Fig.  5  shows  a  furnace  to  be  operated  with  coke,  though 
a  mixture  of  coke  and  smith-coal  free  from  sulphur  may 
also  be  used. 

The  furnace  is  built  of  fire  brick  and  consists,  commenc- 
ing from  below,  of  the  ash-pit  C,  the  grate  r,  the  belly  &,  the 
feeding  funnel  M,  and  the  working  space  A,  the  latter  being 
all  around  provided  with  a  ledge  which  serves  for*  resting 
upon  supports,  articles  which  are  to  be  heated  without  being 
held  by  tongs.  The  working  space  is  terminated  by  a 
small  vault  provided  with  two  to  four  symmetrically 
arranged  apertures  c  d.  These  apertures  are  accessible  by 
means  of  a  door  at  M.  They  serve  chiefly  for  the  purpose 
of  effecting  a  uniform  distribution  of  temperature  in  the 
working  space  A,  and  for  this  purpose  can  be  partially  or 

*The  measurements  given  in  the  illustrations  refer  to  centimeters — 1  centi- 
metre =0.394  inch.  A  comparative  table  of  centimetres  and  inches  will  be 
found  on  the  end  of  the  appendix. 


36 


TOOL-STEEL. 


entirely  closed  by  the  covers  a  b.     The  top  of  the  furnace  is 
closed  by  the  arch  C,  which  carries  the  chimney  E.     If  con- 


FIG.  5. 


nection  is  to  be  made  with  another  chimney  or  with  one 
used  in  common  for  several  furnaces,  the  furnace-gases  are 


FIRE-TREATMENT    OF    STEEL.  37 

conducted  into  it  through  the  space  L,  by  a  flue  branching 
off  sideways. 

To  facilitate  handling  the  tool  to  be  held  in  the  furnace, 
a  table  T  is  placed  in  front  of  the  working-hole  P.  Both  P 
and  the  ash-pit  C  are  to  be  provided  with  well-fitting  sheet 
iron  doors.  The  brick  work  of  the  furnace  is  held  together 
by  clamps  and  bolts  as  shown  in  the  illustration.  For 
regulating  the  draught  the  chimney-flue  is  provided  with  a 
special  damper  or  the  chimney  itself  with  a  movable  cover. 
The  heating  of  such  furnaces  requires  from  one  to  two 
hours  according  to  their  size,  and  is  continued  until  the  in- 
terior of  the  working  space  A,  as  well  as  its  walls,  shows 
a  uniform  bright  red  heat.  The  articles  to  be  heated 
may  now  be  introduced,  the  following  general  rules 
being  observed.  As  the  temperature  rises  considerably 
while  the  furnace  is  in  operation,  work  should  be  com- 
menced with  smaller  pieces  which  are  most  readily  heated 
and  more  exposed  to  the  danger  of  over-heating,  and  then 
pieces  of  larger  dimensions  may  be  gradually  taken  in 
hand.  The  heat  which  is  given  out  by  the  glowing  fuel 
being  greater  than  that  radiated  from  the  furnace  walls,  the 
articles  held  in  the  furnace  are  heated  more  on  one  side 
and  must  therefore  be  frequently  turned.  When  articles  in 
a  cold  state  are  introduced,  fresh  fuel  should  at  the  same 
time  be  supplied,  the  higher  heat  of  the  furnace  being 
thereby  slightly  modified,  and  with  the  use  of  smith-coal 
and  coke  mixed,  the  sooting  flame  developed  affords  some 
protection  against  over-heating  and  oxidation  of  the  edges 
and  corners  of  the  steel.  The  tool-steel  to  be  heated  is 
either  directly  held  with  forge-tongs — the  latter  resting 
upon  the  working  table  T — or  is  laid  upon  a  grate-like  sup- 


38 


TOOL-STEEL, 


port.  Small  tools  which  are  to  be  heated  in  quantities  at  a 
a  time  may  be  brought  into  the  furnace  upon  a  sheet-iron 
support  by  which  they  are  protected  from  the  direct  heat  of 

the  fuel. 

FIG.  6. 


Fig.  6  shows  a  furnace  of  the  same  system  as  Fig.  5,  but 
which  is  operated  with  charcoal.  The  only  difference  is  in 
the  arrangement  of  the  door  for  the  introduction  of  the  fuel, 


FIG.  7. 


it  being  placed  somewhat  higher  to  avoid  useless  consump- 
tion of  charcoal  by  combustion  inside  of  the  filling-box. 


FIRE-TREATMENT    OF    STEEL. 


39 


Fig.  7  shows  the  same  furnace  illustrated  ,by  Fig.  5,  but 
to  save  iron  parts  the  filling-box  and  working  table  are  of 
brick  work. 

Fig.  8  shows  a  furnace  for  heating  long  articles,  for 
instance  long  shear-knives,  saws,  etc.,  for  forging  and 
chiefly  for  hardening. 

The  regulating  apertures,  c  d,  and  their  covers,  a  b,  with 

FIG.  8. 


which  all  the  furnaces  are  provided,  as  well  as  the  chimney- 
damper,  are  of  special  importance  for  operating  this  fur- 
nace. By  opening  or  closing  the  damper  the  draught  in 
the  furnace,  and  thereby  the  temperature  in  it,  is  increased 
or  decreased,  and  by  partly  closing  the  apertures  c  d,  the 
heat  in  separate  parts  of  the  furnace  may  be  raised  or  low- 
ered. Thus  by  closing  the  apertures  c  d  in  the  left  half  of 


40 


TOOL-STEEL. 


the  furnace  (Fig.   8),  the  heat  is  lowered  in  this  portion 
and  raised  in  the  right  half. 

If  the  previously-described  furnaces  are  to  be  fitted  for 
coal,  or  if,  with  the  use  of  hard  coke,  the  articles  to  be 
heated  are  to  be  protected  from  a  possible  contact  with  the 
sharp-pointed  flame  developed  thereby,  the  construction  is 
as  shown  in  Fig.  9. 

FIG.  9. 


The  coal  or  coke  is  here  burnt  under  the  arch  U,  the 
working  space  A  being  heated  through  the  two  slits  Z. 
Thus  the  steel  to  be  heated  does  not  come  in  direct  contact 
with  the  fire  or  the  combustion-gases  of  the  furnace,  heat- 
ing being  effected  under  conditions  similar  to  those  in  a 
muffle. 

By  constructing,  about  10  to  16  inches  above  the  arch  U, 
another  arch  accessible  by  the  door  T,  as  shown  in  Fig.  10, 
the  hearth  thus  obtained  may  be  used  for  preparatory  heat- 
ing. When  room  is  wanting,  the  use  of  such  furnaces  can 
be  recommended  especially  for  continuous  work  in  forging 
and  hardening  articles  on  a  large  scale,  for  instance,  in 


FIRE-TREATMENT    OF    STEEL. 


41 


forging  balls,  files,  shears,  knives,  etc.,  or   in   hardening 
calks  for  horse-shoes,  parts  of  bicycles,  etc. 

By  placing  a  muffle  of  iron  or  clay  upon  the  arch  U  in 
Fig.  9,  or  two  muffles,  one  above  the  other,  as  shown  in 
Fig.  11,  this  furnace  is  converted  into  a  regular  muffle- 
furnace,  the  upper  muffle  serving  for  preparatory  heating. 
In  the  muffle-furnace  the  steel  is  exclusively  heated  by  the 
heat  radiating  from  the  sides  of  the  muffle.  However,  it 
must  not  be  supposed  that  tool-steel  cannot  be  overheated 


FIG.  10. 


FIG.  11. 


in  the  muffle  ;  on  the  contrary,  this  is  very  easily  done  if 
due  care  is  not  observed.  When  a  muffle  furnace  has  been 
in  operation  for  some  time,  so  that  the  walls  of  the  furnace 
and  the  muffle  are  finally  heated  throughout  to  a  high 
degree,  the  heating  of  the  steel  is  also  effected  at  a  higher 
temperature  than  permissible,  and  the  steel  is  overheated, 
or  at  least  the  projecting  corners  and  edges. 

The  interior  of  the  muffle  receives  heat  from  every  por- 


42 


TOOL-STEEL. 


tion  of  the  walls,  but  the  greatest  heat  from  the  portions 
nearest  to  the  fire-place,  therefore  from  the  bottom  of  the 
muffle,  or  from  the  bottom  and  a  side  wall.  Now  if  the 
steel  to  be  heated  is  brought  directly  in  contact  with  the 
walls  of  the  muffle,  the  portions  touching  the  walls  will 
acquire  a  higher  temperature  than  the  rest  and  may  readily 
be  overheated.  Hence,  the  steel  is  placed  upon  supports — 
iron  rods,  or  still  better,  cut  pieces  of  fire-brick — so  that  it 
does  not  come  in  direct  contact  with  the  walls  of  the  muffle 
and  lies  as  nearly  as  possible  in  the  centre.  Uniform  heat- 

FIG.  12. 


ing  is  promoted  by  frequently  turning  the  steel.  To  pre- 
vent the  access  of  air,  the  mouth  of  the  muffle  should  be 
closed  as  tightly  as  possible  by  a  door.  Iron  doors  being 
readily  warped  by  the  heat,  are  not  as  good  for  this  pur- 
pose as  sliding  doors  of  chamotte.  If  an  iron  door  is  used 
it  should  be  provided  in  the  centre  with  a  looking-hole, 
which  can  be  closed,  for  observing  the  temperature  pre- 
vailing in  the  muffle  ;  the  looking-hole  in  the  chamotte 
door  is  tightly  closed  with  isinglass. 

Fig.  12  shows  a  muffle-furnace  to  be  worked  with  char- 


FIRE-TREATMENT    OF    STEEL.  4£ 

coal.     It  serves  for  continuous   heating  of   band-steel  for 
forging,  hardening  and  eventually  for  tempering. 

Muffle-furnaces,  the  muffles  of  which  are  heated  by  gas, 
are  very  cleanly,  and  easily  attended.  Fig.  13  represents 
such  a  furnace.  The  muffle,  3/,  sits  in  an  iron  box,  K, 
which  is  lined  with  chain otte.  Underneath  the  muffle  lies 
a  heating  pipe  provided  with  a  large  number  of  holes  ar- 
ranged in  several  rows,  and  connected  by  means  of  a  pipe 
with  a  small  blower,  V.  The  latter  running  at  a  high 
speed  sucks  gas  from  a  gas-conduit  with  which  it  is  con- 

FIG.  13. 


nected,  mixes  the  gas  with  air  and  conducts  the  mixture  to 
the  heating  pipe.  The  flame  developed  plays  around  the 
muffle  and  rapidly  heats  it  to  a  uniform  temperature, 
which  by  regulating  the  flow  of  gas  can  be  readily  raised 
or  lowered. 

Muffles  of  refractory  clay  must  be  heated  very  slowly 
and  carefully,  otherwise  they  may  crack.  Should  cracks 
nevertheless  be  formed  they  may  be  repaired  with  a  paste 
consisting  of  4  parts  graphite  and  1  part  clay. 

The  above-described  furnaces  are  much  used  in  prac- 
tice, and  when  properly  attended  always  prove  satisfactory. 


44 


TOOL-STEEL. 


The  cost  of  construction  is  not  great,  so  that  their  use  may 
be  especially  recommended  in  works  for  hardening  expen- 
sive tools  where  the  latter  are  still  heated  in  the  open 
forge-fire. 

Although  very  seldom  used  for  hardening,  a  reverbera- 
tory  furnace  is  to  be  preferred  to  a  larger  number  of  forge- 
fires  for  continuous  forging  operations  on  tool  steel. 

Fig.  14  shows  an  ordinary  forging  reverberatory  furnace 

FIG.   14. 


for  heating  with  coal  or  lignite.  It  is  provided  on  each 
side  with  two  working  doors  and  is,  therefore,  suitable  for 
supplying  several  working  places.  Combustion  is  pro- 
moted by  a  blast-pipe  terminating  below  the  grate. 

Fig.  15  shows  the  same  furnace,  the  only  difference  being 


FIRE-TREATMENT    OF    STEEL. 


45 


that  combustion  of  the  coal  is  effected  upon  a  step-grate 
with  free  draught. 

FIG.  15. 


Fig.  16  shows  a  small  reverbatory  furnace  such  as  is  used 
for  forging,  and  also  for  hardening  operations  on  a  small 
scale. 

In  case  room  is  wanting,  and  also  for  small  forging  opera- 


FIG.  16. 


tions,  the  reverberatory  furnace,  Fig.  17,  with  two  hearths 
may  be  used,  the  upper  hearth  serving  for  preparatory 
heating  of  the  articles. 


46 


TOOL-STEEL. 
FIG.   17. 


FIG.  18. 


FORGING   AND   HARDENING   REVERBERATORY   FURNACE. 


FIRE-TREATMENT    OF    STEEL. 


47 


It  must  be  borne  in  mind  that  the  heat  in  a  reverbatory 
furnace  is  not  uniform,  it  being  greater  towards  the  fire- 
place and  less  intense  near  the  working  doors.  Hence  the 
steel  is  first  brought  into  the  colder  portion  of  the  furnace 
and  then  slowly  pushed  towards  the  hotter  portions. 

Articles  to  be  heated  for  hardening  are  brought  into  the 
portion  of  the  reverberatory  furnace  which  shows  the  tem- 
perature to  be  used.  To  avoid  contact  with  the  highly  heated 
bottom  of  the  hearth,  the  articles  are  placed  upon  small  iron 

FIG.  19. 


rods  or  pieces  of  fire  brick,  and  they  are  protected  from  the 
direct  action  of  the  flame  by  placing  a  piece  of  sheet-iron 
bent  at  a  right  angle  in  front  of  them. 

Fig.  18  shows  a  small  reverberatory  furnace  with  step- 
grate  and  two  hearths,  one  above  the  other. 

Fig.  19  illustrates  a  reverberatory  furnace  with  a  fire- 
place patented  by  Gasteiger,  of  Vienna.  It  has  to  some 
extent  been  introduced  in  practice  on  account  of  its  great 
economy  in  the  consumption  of  fuel.  Its  construction  is 
according  to  the  following  principles : 


48 


TOOL-STEEL. 


The  coal  is  piled  upon  the  solid  bottom,  B,  and  gasified. 
The  gases  generated  are  highly  heated  by  passing  over  the 
glowing  coke  upon  the  grate,  R,  and  meeting  the  air,  L, 
which  enters  from  the  sides,  are  burned  in  the  space  A. 

The  heat  thus  produced  is  intensified  by  water-gas,  which 
is  generated  by  steam  evolved  from  a  vessel  filled  with 
water  which  is  fixed  beneath  the  grate,  the  steam  passing 
through  the  layer  of  glowing  coke  upon  the  grate  E. 

FIG.  20. 


Fig.  20  shows  a  reverberatory  furnace  with  muffle  which 
is  extensively  used  for  hardening  and  annealing. 


VI. 


APPLIANCES  FOR  ANNEALING  STEEL. 

As  has  been  mentioned  in  a  previous  chapter,  the  struc- 
ture of  tool-steel  is  profoundly  affected  by  mechanical  work- 
ing, the  grain  being  finer  the  more  vigorously  the  steel  has 
been  worked  and  the  lower  the  temperature  at  which  the 
work  has  been  done. 


APPLIANCES    FOR    ANNEALING    STEEL.  49 

Together  with  this  alteration  in  the  structure  of  the  steel 
its  properties  of  strength  also  undergo  a  change,  the  density 
being  increased,  the  natural  hardness  enhanced  and  the 
capability  of  being  worked  decreased. 

When  in  forging  tool-steel,  some  portions  of  it  are  sub- 
jected to  more  vigorous  mechanical  working  than  others, 
and  some  portions  remain  almost  untouched,  the  tool  made 
from  such  steel  showing  in  these  places  different  degrees  of 
strength  as  well  as  a  different  structure,  and  is  said  to  have 
forging  strains.  In  the  further  manipulation  of  such  tool  it 
works  very  unevenly  and  generally  cracks  in  the  subse- 
quent hardening. 

To  take  these  strains  out  of  the  forged  tools  or  to  im- 
prove the  capacity  of  crude  steel  for  being  worked,  they  are 
annealed  before  being  worked. 

In  annealing  tool-steel  the  same  attention  and  care  must 
be  observed  as  in  all  other  heating  operations. 

The  following  general  rule  applies  to  annealing : 

The  steel  should  be  heated  as  slowly  and  uniformly  as 
possible  to  a  cherry-red  heat  and  kept  at  this  temperature 
until  it  may  be  supposed  to  have  acquired  a  uniform  heat 
throughout.  It  should  then  be  protected  against  too  rapid 
a  loss  of  heat  and  allowed  slowly  to  cool. 

When,  in  annealing,  tool-steel  is  exposed  to  the  action  of 
the  air  it  becomes  coated  with  a  layer  of  oxide  which  fre- 
quently penetrates  to  some  depth.  The  steel  may  even  lose 
carbon  on  the  surface,  the  decarbonized  places  acquiring  no 
longer  a  sufficient  degree  of  hardness,  and  at  a  high  tem- 
perature the  steel  may  readily  be  overheated  and  burnt. 

Hence  to  protect  tool-steel  from  the  action  of  the  air  it  is 
frequently  annealed  in  vessels.  Overheating  in  annealing 
4 


50  TOOL-STEEL. 

can  only  be  prevented  by  scrupulous  observation  of  the 
temperature. 

Regarding  the  practical  execution  of  annealing  the  fol- 
lowing hints  may  be  given  : 

Single  tools  or  pieces  of  steel  may  be  annealed  in  any 
of  the  furnaces  previously  described.  When  heating  has 
progressed  so  far  that  the  articles  show  a  uniform  red  heat, 
they  are  imbedded  in  charcoal  so  as  to  be  completely 
covered,  and  allowed  slowly  to  cool.  For  annealing  articles 
of  steel  of  special  hardness  sheet-iron  vessels,  or  cast-iron 
boxes  especially  made  for  this  purpose  are  used.  The 
articles  are  packed  in  the  boxes  between  thoroughly  burned 
charcoal,  horn  shavings,  iron  shavings  free  from  rust,  and 
the  like.  The  covers  of  the  boxes  and  any  cracks  are  luted 
with  clay,  and  the  boxes  are  then  heated,  the  same  precau- 
tions as  with  steel  not  packed  being  observed.  When  suffi- 
ciently heated  the  boxes  are  covered  with  charcoal  and 
allowed  slowly  to  cool.  The  annealed  articles  should  be 
taken  from  the  protecting  covering  only  when  thoroughly 
cold. 

For  annealing  larger  quantities  of  tool-steel  or  manufac- 
tured articles,  it  is  advisable,  especially  if  the  operation  is 
to  be  frequently  repeated,  to  construct  special  annealing 
furnaces. 

Fig.  21  shows  an  annealing  furnace  for  forged  pieces,  for 
instance  cutters,  files,  swages,  parts  of  bicycles,  etc.,  or  for 
tool-steel  in  short  pieces.  Wood  and  peat  are  chiefly  used 
as  fuel.  Fuels  yielding  a  quick  heat  should  not  be  em- 
ployed. 

The  pieces  of  steel  or  the  articles  are  piled  upon  the 
hearth-bottom  so  that  they  are  at  a  distance  of  a  few  centi- 


APPLIANCES    FOR    ANNEALING    STEEL. 


51 


metres  from  the  openings  m  mm;  in  no  case  should  they 
extend  beyond  them.     The  working  door  is  then  closed  or 


the  door-opening  bricked  up   with   fire   brick,   the  joints 
being  thoroughly  filled  up  with  clay.     For  observing  the 


52 


TOOL-STEEL. 


temperature  in  the  furnace  looking-holes  furnished  with 
slides  are  arranged  in  the  door  and  side  walls. 

The  furnace  is  first  heated  with  small  quantities  of  fuel, 
firing  being  increased  as  the  temperature  rises  until  the 
steel  shows  throughout  a  uniform,  not  too  bright,  cherry-red 
heat.  This  temperature  is  attained  in  four  to  eight  hours, 
according  to  the  capacity  of  the  furnace.  All  the  flues 
serving  for  regulating  the  work  of  the  furnace  are  now 
closed,  as  well  as  the  chimney-damper  and  the  doors,  and 
cracks  through  which  air  might  penetrate  into  the  furnace 
are  filled  up  with  clay.  The  furnace  is  then  allowed  to  cool 
slowly,  which  requires  48  to  72  hours. 

Tool-steel  thus  annealed  is  of  a  very  uniform,  soft  quality. 

FIG.  22. 


The  same  process  of  operating  is  to  be  observed  in  anneal- 
ing steel  in  any  of  the  furnaces  previously  described. 

The  furnace,  Fig.  21,  may  also  be  used  for  annealing 
steel  in  an  annealing  pot  or  in  annealing  boxes,  the  latter 
when  filled  being  placed  upon  the  hearth-bottom  and 
heated  in  exactly  the  same  manner  as  above  described.  In 
this  case  coal  may  also  be  used  as  fuel. 

The  mode  of  arrangement  will  be  seen  from  Figs.  21 
and  22. 


APPLIANCES    FOR    ANNEALING    STEEL. 


Fig.  23  shows  a  furnace  with  a  large  annealing  pot,  and 
Fig.  24,  one  with  a  larger  number  of  smaller  annealing 
pots. 

FIG.  23. 


Regarding  these  furnaces,  it  may  be  mentioned  that  the 
annealing  pots  may  readily  be  unevenly  heated  by  the 
surrounding  flame,  in  consequence  of  which  the  articles 


FIG.  24. 


ro 


will  be  partially  overheated,  and  in  the  subsequent  hard- 
ening yield  much  waste.  However,  by  very  slow  heating 
and  constant  attention  this  trouble  can  be  avoided. 


54 


TOOL-bTEEL. 


For  the  control  of  the  result  of  the  annealing  operation, 
small  rods  of  steel — waste  or  ends  of  the  same  quality  of 


steel — are  added  to  the  articles  to  be  annealed  and  placed 
in  the  parts  of  the  furnace  or  annealing  pots  where  over- 


APPLIANCES    FOR    HARDENING    STEEL.  55 

heating  may  readily  take  place.  When  annealing  is  fin- 
ished, the  rods  are  broken,  and  by  comparing  the  resulting 
fracture  with  that  of  crude  steel,  a  conclusion  may  be 
drawn  as  to  the  temperature  attained  in  the  annealing 
furnace. 

Fig.  25  shows  an  annealing  furnace  for  annealing  long 
articles,  of  the  same  system  as  that  represented  by  Fig.  20. 


VII. 

APPLIANCES  FOR  HARDENING  STEEL. 

THE  various  furnaces  shown  in  Figs.  2  to  19  inclusive 
serve  aJso  for  heating  steel  for  hardening. 

In  no  other  operation  in  the  manufacture  of  tools  is 
thoroughly  uniform  heating  of  such  importance  as  in  hard- 
ening. The  slightest  error  committed  here  causes  damage 
which  cannot  be  repaired. 

Great  care  should  therefore  be  exercised  in  the  selection 
of  furnaces  for  hardening,  since  in  case  the  tool  is  spoiled, 
there  is  the  additional  loss  of  the  cost  of  producing  it. 

Unfortunately  there  are  no  perfect  appliances  by  means 
of  which  reliable  heating  of  the  tool  can  be  automatically 
effected,  the  success  of  the  operation  depending  in  this  re- 
spect always  on  the  experience  and  attention  of  the  hardener. 

Imperfect  heating  appliances  require  closer  attention 
and  the  observance  of  numerous  rules,  which  soon  tires  the 
hardener,  and  many  contingencies  arise,  the  result  being 
defective,  or  entirely  useless,  tools.  Hence  appliances 


56  TOOL-STEEL. 

should  be  provided  which  do  not  require  such  close  atten- 
tion as  to  make  too  great  a  demand  on  the  skill  of  the 
hardener. 

In  reference  to  the  choice  of  suitable  appliances,  the 
following  hints  may  here  be  given  : 

If  for  hardening  tools  no  other  contrivance  than  an  open 
fire  is  available,  charcoal  should  be  exclusively  used  for 
heating,  even  if  it  is  thought  that  for  momentary  use  other 
fuel  might  answer.  The  result  of  a  change  of  fuel  in  favor 
of  charcoal  will  in  a  short  time  show  itself  in  the  better 
quality,  greater  uniformity  and  longer  endurance  of  the 
finished  tool. 

The  devices  shownr  in  Figs.  3  and  4  may  in  many 
cases  be  employed  with  good  results,  for  instance,  for  occas- 
ionally hardening  fine  tools,  such  as  iwist  drills,  broaches, 
cutters,  etc. 

By  reason  of  their  simple  construction  and  their  small 
cost,  the  furnaces,  Figs.  5  to  7  inclusive,  may  be  especially 
recommended  for  hardening  all  kinds  of  tools.  With  the 
use  of  charcoal  as  fuel,  hardening  is  readily  executed  and 
without  great  danger  even  for  the  most  complicated  tools. 

The  furnace,  Fig.  8,  should  not  be  wanting  in  a  work- 
shop where  long  articles,  especially  shear-knives,  are  hard- 
ened. 

The  various  muffle  furnaces  previously  described  and 
illustrated  are  of  all  the  furnaces  best  adapted  for  harden- 
ing, and  offer  the  further  advantage  that  fuel  may  be  em- 
ployed, the  use  of  which  in  other  furnaces  might  be  injuri- 
ous to  the  steel. 

Although  in  the  muffle  furnace  the  tool  does  not  come  in 
direct  contact  with  the  fuel  or  its  gases,  the  access  of  air  to 


APPLIANCES    FOR    HARDENING    STEEL. 


57 


it  cannot  be  entirely  avoided.  Besides,  by  the  tool  coming 
in  direct  contact  with  the  walls  of  the  muffle,  it  may  be  un- 
evenly heated,  and  hence  still  safer  methods  are  in  many 
cases  desirable.  The  tools  to  be  hardened  are  then  heated 
so  that  the  air  is  absolutely  excluded,  either, 

1.  In  a  bath  of  molten  metal,  or, 

2.  In  a  bath  of  fused  salts  of  a  determined  melting  tem- 
perature. 

Before  entering  into  the  further  discussion  of  these 
methods,  it  may  be  mentioned  that  in  a  melted  mass  tools 
may  also  be  heated  too  high  as  well  as  too  low.  The  mere 
heating  in  it  offers  no  guarantee  against  the  above-men- 
tioned defects,  if  the  melted  mass  itself  has  been  heated  too 
high  or  not  uniformly.  It  can  just  as  readily  be  over- 
heated as  the  wall  of  the  muffle  or  a  piece  of  steel,  and  its 
being  in  a  fluid  state  does  not  prevent  unequal  heating,  just 

FIG.  26. 


the  same  as  with  water  which  in  a  vessel  may  be  brought 
to  boiling  on  the  surface  without  raising  the  heat  lower 
down. 


58 


TOOL-STEEL. 


FIG.   27. 


The  metals  or  salts  are  melted  in  a  cast-iron  crucible,. 

generally    of  a   round   cross-section,   which    is   built   in   a 

furnace  as  shown  in  Fig.  26.     The  crucible  is  heated  with 

coke  yielding  a  mild  heat,  or  still  better,  with  charcoal. 

Fig.  27  shows  a  furnace  which  may   be  operated  with 

wood    or    coal,    and    also    with, 
lignite. 

Without  the  use  of  a  pyro- 
meter, the  temperature  of  the 
melted  mass  is  controlled  with 
difficulty,  and  can  only  be  judged 
by  the  glow  of  the  article  heated 
in  it.  A  pyrometer  is  also  of  great 
service  for  an  annealing  furnace. 

Of  the  metals  in  a  fluid  state  which  serve  for  heating 
steel,  refined  lead  without  any  additions  is  mostly  used. 
Since  lead  melts  at  637°  F.,  and  must  be  superheated  ta 
about  1382°  F.  in  order  to  attain  the  required  hardening 
temperature,  it  is  exposed  to  strong  oxidation  on  the  sur- 
face, and  the  loss  by  evaporation  is  very  large.  To  decrease 
this  loss  by  oxidation,  the  surface  of  the  melted  metal  is 
covered  about  J  to  f  inch  deep  with  powdered  charcoal. 
The  lead  vapors,  which  are  very  injurious  to  the  respiratory 
organs,  are  carried  off  through  a  chimney  indicated  in  Figs. 
26  and  27. 

Besides  unequal  heating  or  over-heating,  the  disadvan- 
tages which  may  arise  from  heating  steel  in  melted  lead  are 
as  follows :  Impure  lead  containing  sulphur  yields  a  por- 
tion of  the  latter  to  the  steel,  the  previously  described  soft 
spots  being  formed.  Hence,  to  be  sure,  the  freshly  melted 
lead  is  for  a  few  hours  boiled  before  being  used.  When 


APPLIANCES    FOR    HARDENING    STEEL.  59 

tools  are  heated  in  melted  lead  some  of  the  latter  readily 
adheres  to  some  portions — in  corners,  on  teeth,  or  other  de- 
pressions— and  prevents  the  hardening  fluid  from  coming 
on  these  places  in  contact  with  the  tool,  and  the  latter 
here  and  there  remains  soft.  To  avoid  this,  cleanse  the 
tools  before  hardening  with  benzine  or  alcohol  from  adher- 
ing grease,  and  brush  them  over  with  a  mass  of  dough-like 
consistency  prepared  by  mixing  1  part  by  volume  of  finely 
powdered  charcoal  (charred  leather),  1  part  by  volume  of 
rye  flour  and  1  part  by  volume  of  common  salt  with 
saturated  solution  of  common  salt  in  water. 

Dry  slowly  and  carefully  the  articles  brushed  over  with 
this  mixture  before  immersing  them  in  the  melted  lead 
bath. 

Although  heating  steel  in  fused  salts  may  be  designated 
as  one  of  the  best  methods,  it  is  not  very  widely  practised, 
but  where  it  is  in  use  the  great  advantages  offered  by  it  are 
highly  appreciated. 

No  absolute  rule  as  to  the  mixture  of  salts  to  be  fused 
can  be  given,  it  depending  chiefly  on  the  purpose  it  is  to 
serve.  Pure  readily-fusible  salts  which,  when  heated  above 
their  melting  points,  rapidly  volatilize  are,  of  course,  un- 
suitable, as  well  as  salts  which,  by  reason  of  their  chemical 
composition,  exert  an  injurious  effect  upon  the  steel  to  be 
heated  in  them. 

On  account  of  its  special  fitness  and  cheapness,  common 
salt  forms  the  chief  constituent  of  the  mixture.  By  the 
addition  of  a  small  quantity  of  readily-fusible  soda  (carbon- 
ate of  soda),  fusion  of  the  common  salt  is  accelerated,  and 
the  fluidity  of  the  melted  mass  is  increased  by  an  addition 
of  a  small  quantity  of  saltpetre.  An  addition  of  potassium 


60  TOOL-STEEL. 

chromate  or  of  borax  improves  the  properties  of  the  bath, 
as  well  as  an  addition  of  yellow  prussiate  of  potash,  a  pos- 
sible injurious  effect  of  the  saltpetre,  by  decarbonizing  the 
steel,  being  thereby  prevented. 

The  salt  is  fused  in  a  cast-iron  crucible  bricked  in  a  fur- 
nace, such  as  shown  in  Figs.  25  and  26,  the  operation  being 
as  follows :  Cover  the  bottom  of  the  crucible,  about  one- 
third  inch  deep,  with  soda  solidly  rammed  down,  and  fill 
the  crucible  up  to  the  edge  with  common  salt.  Then  heat 
the  whole  until  fusion  is  complete.  Now  add  gradually  to 
the  melt  enough  common  salt  sufficiently  to  fill  the  cruci- 
ble, and  then  add  about  5  per  cent,  by  volume  of  saltpetre 
and  10  to  15  per  cent,  of  potassium  chromate. 

Yellow  prussiate  of  potash  in  small  pieces  is  added  to 
the  melt  as  required,  a  larger  quantity  of  it  being  used  if 
the  cementing  effect  is  to  be  increased.  In  using  yellow 
prussiate  of  potash  it  must  be  borne  in  mind  that  the 
vapors  evolved  are  very  poisonous  and  should  be  removed 
by  means  of  a  pipe. 

As  regards  the  condition  of  the  articles  to  be  heated,  it 
may  be  mentioned  that  they  must  be  free  from  liquid  im- 
purities ;  adhering  oil  or  fluid  fats  must  be  previously 
removed  by  means  of  benzine  or  alcohol.  Water  should 
be  particularly  avoided,  as  the  introduction  of  moist  articles 
might  readily  cause  an  explosive  ejection  of  the  melted 
mass.  Very  cold  articles  should  be  warmed  before  being 
immersed  in  the  melt. 

The  articles  are  suspended  in  the  melt  by  small  hooks, 
or  they  may  be  secured  by  ordinary  iron  wire.  Articles 
which  are  to  be  partially  hardened  are  held  with  tongs 
which  should  be  perfectly  dry. 


APPLIANCES    FOR    HARDENING   STEEL.  61 

With  this  method  it  is  of  course  also  possible  to  overheat 
the  melt,  but  this  soon  causes  bubbling  and  -running  over, 
so  that  it  can  be  more  readily  avoided  than  with  the  use  of 
lead.  However,  unequal  heating  of  the  melt  may  readily 
occur.  It  may  be  detected  by  pushing  a  steel  rod  into  the 
melt  and  observing  the  degrees  of  heating  of  various  parts 
of  it ;  the  working  of  the  furnace  is  regulated  accordingly. 

The  disadvantages  due  to  melted  lead  sticking  to  the  tool 
are  avoided  with  this  method,  the  salt  coating  cracking  off 
immediately  from  the  tool  when  the  latter  is  plunged  ia 
water. 

The  tools  heated  in  melted  salt  retain  their  pure  metallic 
surface  after  hardening.  Articles  which  before  hardening 
are  coated  with  a  layer  of  oxide,  show  after  hardening  a 
pure,  smooth  surface  free  from  all  scale.  When  to  the  salt 
melt  larger  quantities  of  yellow  prussiate  of  potash  are 
gradually  added  it  exerts,  in  heating  iron  and  steel,  a  strong 
cementing  effect,  so  that  wrought  iron,  otherwise  not  capa- 
ble of  being  hardened,  acquires,  when  treated  in  it,  a  surface 
as  hard  as  glass,  and  the  hardness  of  steel  is  not  immateri- 
ally increased. 


62  TOOL-STEEL. 

VIII. 

HARDENING  OF  TOOL-STEEL  IN  GENERAL. 

BY  hardening  is  understood  the  rapid  cooling  of  steel 
from  a  distinctly  perceptible  red  heat  to  a  lower  degree  of 
temperature. 

Before  discussing  the  means  which  may  be  employed  for 
cooling  the  steel  to  be  hardened,  it  is  necessary  to  refer  to 
the  changes  the  steel  undergoes  in  hardening. 

Steel  when  being  heated  for  hardening  must  acquire  a 
certain  temperature  if,  after  the  subsequent  rapid  cooling, 
it  shall  possess  hardness.  The  hardening  temperature  to 
be  employed  lies  between  1292°  and  1482°  F.,  it  being 
closer  to  the  former  for  hard  steel  and  closer  to  the  latter 
for  soft  steel. 

Hardened  steel  when  gradually  reheated  to  a  higher 
temperature  constantly  loses  in  hardness,  and  has  lost  it 
entirely  on  acquiring  a  dark  brown-red  heat  which  is  per- 
ceptible only  in  a  dark  room. 

If  the  steel  thus  heated  possesses  a  pure  metallic  surface, 
the  latter,  on  heating,  becomes  coated  with  a  film  of  iron 
oxide  (ferroso-ferric  oxide)  which  shows  different  colors  at 
various  degrees  of  heat.  By  this  color — called  temper-color 
— appearing  upon  the  surface  of  the  steel  it  may  be  judged 
what  degree  of  temperature  has  been  attained,  and  also 
whether  heating  has  been  uniform  and  sufficiently  high  for 
the  desired  degree  of  hardness. 

With  steel  of  different  degrees  of  hardness,  the  temper- 
colors  do  not  appear  at  exactly  the  same  temperature. 
Hence  their  selection  depends  on  the  character  of  the  steel 


HARDENING    OF    TOOL-STEEL.  63 

used,  but  primarily  on  the  degree  of  hardness  previously 
given  to  the  steel,  and  on  the  purpose  for  which  the  tool  is 
to  be  used. 

It  is  generally  customary  to  temper  the  finished  tools 
before  they  are  used  in  order  to  lessen  the  brittleness  in  a 
hardened  state  and  to  impart  to  them  the  degree  of  tough- 
ness required  to  save  the  parts  engaged  in  use  from 
breaking. 

For  the  reason  previously  mentioned,  only  general  hints, 
which  will  be  found  in  the  table,  facing  p.  22,  can  be  given 
for  the  selection  of  the  temper  colors. 

For  the  appearance  of  the  temper  colors  it  is  absolutely 
necessary  for  the  pure  metallic  surface  of  the  heated  steel 
to  come  in  contact  with  the  air.  Perceptible  temper  colors 
do  not  appear  on  impure  surfaces,  for  instance,  such  as  are 
•covered  with  fat  or  other  substances,  nor  on  steel  which, 
for  the  purpose  of  being  tempered,  is  immersed  in  melted 
metal  of  a  fixed  temperature. 

The  changes  which  steel  undergoes  in  hardening  are 
chiefly  due  to  the  condition  in  which  it  was  previous  to 
this  operation.  By  rapid  cooling  the  hardening  carbon 
which  is  formed  by  heating  the  steel  becomes  fixed  and 
the  structure  of  the  steel  concretes  in  the  same  condition 
in  which  it  was  at  the  time  of  hardening.  This  fixation 
extends  also  to  the  volume  of  the  steel.  Steel,  like  nearly 
all  other  metals,  expands  by  heating,  its  volume  being 
increased  in  the  direction  of  definite  dimensions.  In  hard- 
ening steel,  i.  e.,  by  rapid  cooling  in  a  lower  temperature, 
heat  is  so  rapidly  withdrawn  from  it  as  to  give  the  harden- 
ing carbon  no  time  to  be  reconverted  into  carbide  carbon, 
in  which  state  the  carbon  occurs  in  unhardened  steel. 


64  TOOL-STEEL. 

The  structure  of  the  steel  attains  a  state  of  rigidity  and 
in  this  condition  opposes  considerably  more  resistance  to  a 
change  in  form  than  before,  and  in  overcoming  this  resist- 
ance the  component  parts  of  the  structure  are  not  displaced 
but  completely  separated  (torn,  broken). 

Hardened  steel  can  no  longer  contract,  and  when  once 
hardened  also  retains  the  larger  volume  which  it  possessed 
in  the  heated  state.  The  fixed  dimensions  in  the  direction 
of  thickness,  and  to  a  more  limited  extent,  in  that  of 
breadth,  are  greater  after  hardening,  while  the  length  of 
hardened  steel  is  less  than  previous  to  hardening. 

These  changes  in  the  dimensions  of  the  steel  can  practic- 
ally be  determined  only  with  very  accurate  measuring  in- 
struments, though  under  certain  conditions  they  become  so 
great  as  to  be  perceptible  to  the  naked  eye.  This  may 
be  observed  on  tool  steel  which  has  been  repeatedly  hard- 
ened without  being  annealed  before  each  hardening. 

When  a  piece  of  flat  steel  about  1J  inches  wide,  0.39 
inch  thick  and  3J  to  6  inches  long,  or  a  crude  cutter  about 
1}  inches  in  circumference  and  0.47  to  0.59  inch  thick,  is 
hardened,  then   returned    to  the  fire,  and    after   carefully 
F     2g  heating     to     the     hardening 

temperature,  again  hardened, 
and  these  operations  be  re- 
peated ten  to  twenty  times, 
the  changes  in  volume  which 
the  steel  suffers  are  very  con- 
spicuous, and  the  changes  will 
be  the  greater  the  harder  the  steel  is.  They  are  illustrated 
in  cross-section  in  Fig.  28.  For  the  experiment  a  steel 
plate  with  1  per  cent,  carbon  and  3.071  inches  long,  1.732 


HARDENING    OF    TOOL-STEEL.  65 

inches  wide  and  0.315  inch  thick  was  used  and  hardened 
fifty-one  times. 

Repeated  hardening  could  by  no  means  cause  such  con- 
siderable changes  in  form  if  the  steel  every  time  it  was 
heated  previous  to  hardening  would  reassume  its  original 
dimensions.  Such  is  the  case  only  when  the  steel  after 
heating  is  allowed  slowly  to  cool.  Simply  heating  the  steel 
before  hardening  is  not  equivalent  to  annealing,  if  heating 
is  not  succeeded  by  slow  cooling. 

Strains  which  were  in  the  steel  before  it  is  hardened  are 
not  removed  by  simply  heating  in  hardening,  but  are  even 
increased  or  enhanced  after  this  operation.  Special  stress 
must  be  laid  on  this,  because  the  incorrect  view  is  very 
frequently  held  that  heating  before  hardening  is  equivalent 
to  annealing,  and  that  such  heating  suffices  for  the  compen- 
sation of  the  strains  in  the  steel.  As  mentioned  in  a  pre- 
vious chapter,  in  working  steel  its  structure  undergoes  a 
change,  it  becoming  the  denser  the  more  vigorously  the 
steel  had  previously  been  worked  and  the  lower  the  tem- 
perature at  which  the  operation  had  been  performed.  The 
steel  decreases  in  volume  while  its  specific  gravity  becomes 
higher.  The  component  parts  of  the  structure  are  then 
under  the  same  influence  as  in  hardened  steel,  i.  e.,  in  a  state 
of  rigidity  which  is  much  increased  by  hardening  if  the 
steel  is  not  previously  annealed.  Hence  there  is  greater 
danger  of  cracks  being  formed  in  consequence  of  the 
greater  brittleness  of  steel  not  annealed. 

The  above  described  property  of  steel  of  assuming  fixed 
dimensions  in  hardening  operations  immediately  succeeding 
one  another  is  practically  utilized,  for  instance,  with  draw- 
plates.  When  the  hole  by  use  has  been  enlarged,  the 
5 


66  TOOL-STEEL. 

draw-plate  is  hardened  without  previous  annealing,  the 
result  after  each  repetition  of  the  process  being  a  contrac- 
tion of  the  hole.  If  tool-steel  of  the  same  degree  of  hard- 
ness of,  for  instance,  a  round  or  square  cross-section,  be 
notched  at  distances  of  about  J,  1  and  1J  inches  from  each 
other,  and  then  hardened  and  broken  on  the  notched  places, 
the  fractures  allow  of  the  following  observations  being 
made : 

The  steel  with  the  smallest  cross-section  will  throughout 
show  a  uniform,  fine  structure  over  the  entire  fracture  if 
the  steel  used  for  the  experiment  contained  more  than 
about  }  per  cent,  carbon,  and  heating  before  hardening 
had  been  uniform  throughout.  The  heat  from  the  interior 
of  the  steel  has  been  yielded  up  to  the  hardening  fluid  with 
sufficient  rapidity  to  produce  uniform  hardening  through- 
out the  entire  cross-section. 

On  the  fracture  of  the  steel  with  medium  cross-section 
will  be  noticed  a  symmetrically  arranged  core  of  coarser 
structure,  which  shows  quite  sharply  defined  boundaries. 
The  hardness  of  this  core  will  be  somewhat  less  than  that 
of  the  surface.  The  delivery  of  heat  from  the  interior 
could  not  progress  rapidly  enough,  and  the  hardness  is  not 
so  great  as  on  the  surface ;  hence  the  structure  remains 
coarser. 

This  phenomenon  is  still  more  strikingly  perceptible  on 
the  fracture  of  the  steel  with  a  larger  cross-section.  The 
interior  of  the  steel  shows,  increasing  towards  the  centre,  a 
coarser  structure  and  considerably  less  hardness  than  on 
the  outer  edges. 

The  above  described  phenomenon  is  seldom  sufficiently 
taken  into  consideration.  However,  when  considered  in 


HARDENING    OF    TOOL-STEEL.  67 

connection  with  the  fact  that  hardened  steel  increases  in 
volume,  it  is  of  the  greatest  importance  for  the  practice  of 
hardening,  especially  as  regards  the  mode  of  cooling  the 
steel  to  be  hardened. 

In  Fig.  29  the  dotted  line  represents  the  cross-section  of 
steel   not  hardened,  and  the  full   line  the          FIG  29 
cross-section    of  the   same    steel    hardened. 
By    two   concentric   circles    the   surface   is 
divided  into  three  parts,  of  which  a  repre- 
sents the  surface  of  greatest  hardness,  b  that 
of  less,  and  c  that  of  least,  hardness. 

Assume  the  zones  thus  formed  to  be  continued  through- 
out the  entire  piece  of  steel,  spaces  are  formed  inside 
of  which  the  steel  is  of  approximately  the  same  char- 
acter. For  instance,  in  the  space  a  the  steel  acquired  the 
greatest  hardness  and  in  consequence  also  the  greatest  per- 
manent expansion;  in  the  space  b  the  hardness  as  well  as 
the  permanent  expansion  is  less,  the  steel  in  consequence 
of  slower  cooling  having  a  tendency  to  contract  somewhat 
in  this  zone.  In  the  space  c  the  delivery  of  heat  proceeded 
still  more  slowly,  and  the  steel  has  the  least  hardness  and 
the  greatest  tendency  to  occupy  the  original  volume  it 
possessed  before  hardening,  i.  e.,  to  contract. 

Now,  if  instead  of  two  zones,  we  assume  the  interior  of 
the  steel  to  be  divided  into  innumerable  such  zones,  it  may 
be  imagined  that  each  zone  in  its  endeavor  to  contract, 
exerts,  commencing  from  the  surface  towards  the  centre,  a 
strain  of  constantly  increasing  force  upon  the  outer  portions 
of  the  steel. 

When  the  force  of  the  strain  developed  in  the  separate 
parts  has  become  so  great  as  to  overcome  the  strength  of 


68  TOOL-STEEL. 

the  steel,  a  displacement  of  the  particles  of  its  structure 
takes  place,  the  steel  suffering  an  expansion,  whereby  the 
force  of  the  strain  is  checked  or  diminished.  The  greater 
the  degree  of  hardness  which  the  steel  possesses,  the  less  it 
will  be  capable  of  expanding,  and  the  sooner  a  separation 
of  the  particles  of  the  structure  and  consequently  cracking 
will  take  place. 

This  cracking  of  the  steel,  however,  does  not  always  orig- 
inate in  the  portions  where  the  most  powerful  strain  pre- 
vails, but  in  the  portions  of  the  steel  which  possess  the  least 
degree  of  extensibility  and  toughness.  This  is  generally 
the  case  on  the  corners  and  edges,  they  being  hardest,  and 
seldom  in  the  body  of  the  tool,  the  softer  core  of  which  will 
expand  without  cracking. 

The  strains  in  the  interior  of  the  steel  may,  however,  be 
so  great  that  the  limit  of  extension  of  which  the  less  hard 
core  is  capable  is  exceeded.*  The  formation  of  the  crack 
then  commences  in  the  interior  of  the  steel. 

While  cracks  commencing  on  or  near  the  surface  are,  as 
a  rule,  formed  early  in  the  hardening  fluid,  and  are  per- 
ceptible immediately  after  hardening,  severance  in  the 
interior  generally  takes  place  a  considerable  time  after 
hardening  and  frequently  causes  the  hardened  tool  to  break 
only  after  several  days. 

Cracking  which  had  its  origin  in  the  interior  may  fre- 
quently be  observed  on  tools  with  a  symmetrical  cross- 

*  When  the  interior  of  the  steel  has  flaws  due  to  blisters  or  pipes,  or  when 
in  consequence  of  liquidation,  the  steel  is  of  varying  chemical  composition, 
the  formation  of  cracks  is  the  more  sure  to  commence  from  the  interior.  The 
cause  of  this — a  defect  in  the  steel — is,  however,  plainly  perceptible  on  the 
fracture. 


HARDENING    OF    TOOL-STEEL. 


69 


section  and  on  large  dimensions,  as  well  as  when  hard  steel 
has  been  used,  because  with  a  symmetrical  cross-section  the 
centre  of  the  steel  is  simultaneously  subjected  from  several 
sides  to  a  powerful  strain,  and  in  hard  steel  the  strains  are 
particularly  great,  its  toughness  being  but  slight. 

Thin  flat  steel,  profile  steel  of  slight  thickness,  etc.,  are 
less  liable  to  cracking  in  the  interior  than  round  or  square 
steel,  or  cubes  and  balls. 

In  observing  the  fracture  of  hardened  steel  of  a  larger 
cross-section,  it  will  be  noticed  that  a  narrower  or  wider 
border  of  an  entirely  uniform  structure  and  equal  hardness 
passes  abruptly  into  an  endless  curved  core  of  less  hardness 
and  of  coarser  structure.  On  the  boundary  between  both 

FIG.  30. 


of  them,  close  to  the  surface,  are  located  the  greatest  strains, 
the  steel  possessing  here  the  least  toughness,  and  it  cracks 
along  the  course  of  this  boundary,  hence  generally  in  a 
curve.  The  corners  of  a  cube,  if  the  latter  be  repeatedly 
heated,  will  be  severed,  as  shown  in  Fig.  30,  in  the  first 
hardening  if  the  steel  is  brittle  or  has  become  so  by  over- 
heating. The  severance  of  the  teeth  of  cutters  also  takes 
place  in  a  line  running  in  a  curve  along  the  boundary 
above  described,  and  that  of  the  face  of  a  hammer  as 
sketched  in  Fig.  31. 


70 


TOOL-STEEL 


The  force  of  the  strain  in  forming  cracks  may  frequently 
be  so  excessive,  especially  with  hard  steel,  that  when  the 
latter  cracks  the  fragments  are  hurled  about  with  great 
force. 

FIG.  31. 


Fig.  32  represents  a  round  bar  of  particularly  hard 
special  steel  which,  after  hardening,  has  cracked  from  the 
interior.  The  force  of  strain  exerted  upon  the  interior  of 
the  steel  may  be  judged  from  the  manner  in  which  the  two 
halves  are  bent. 


FIG.  32. 


FIG.  33. 


Fig.  33  shows  a  roll-cutter,  the  corners  of  which  have 
been  severed  during  the  hardening  in  the  direction  of  the 
above-mentioned  curved  line. 

The  above-mentioned  forces  are  at  work  at  every 
hardened  tool  and  frequently  cause  cracking,  even  with 
the  use  of  sound  steel,  if  hardening  has  been  done  in  a 
faulty  manner,  and  it  has  been  neglected  to  lessen  the 
brittleness  of  the  hardened  steel  by  annealing  at  the  proper 
time. 

The  previously  described  strains  which  in  hardening  are 
formed  in  the  direction  of  the  cross-section  by  an  increase 


HARDENING    OF    TOOL-STEEL.  71 

in  the  dimensions  in  the  directions  of  the  width  and  the 
thickness  are  highly  influenced  by  the  strains  which  are 
formed  in  consequence  of  the  steel  contracting  in  hardening. 
The  effect  of  these  strains  may  be  readily  followed  up  by 
bearing  in  mind  that  the  outermost  layer  of  the  steel  which 
has  been  uniformly  hardened  has  experienced  a  contraction, 
while  the  more  slowly  cooling  core  has  a  tendency  to  ex- 
pand. In  consequence  of  this,  strains  are  formed  in  the 
layer  of  greatest  hardness  parallel  to  the  direction  of  its 
length.  These  strains  in  the  direction  of  the  length  cause 
a  distortion  of  the  steel  if  the  latter  has  not  been  uniformly 
cooled  in  hardening.  When  a  flat  bar  of  steel  is  uniformly 
heated  and  the  edge  is  lengthwise  plunged  in  water  so  that 
about  one-half  of  its  width  is  cooled,  it  contracts  on  this 
side,  while  the  uncooled  portion  projecting  from  the  water 
expands.  In  consequence  of  these  forces  acting  in  a  dis- 
similar manner,  the  steel  acquires  the  form  of  a  sickle,  the 

FIG.  34. 

Before  tfttr 


hardened    portion  curving  inwardly  and  the  unhardened 
portion  outwardly. 

If  the  bar  of  steel  be  bent  together  to  a  ring  not  entirely 
closed,  and  is  then  heated  red  hot,  and  the  outer  side  of  the 
ring  is  rapidly  cooled,  it  will  contract  and  cause  the  ring  to 
open,  see  Fig.  34. 


72  TOOL-STEEL. 

In  hardening  tools  of  an  annular  cross-section,  the  cir- 
cumference becomes  smaller,  while  the  interior  layers  which 
have  been  less  cooled  endeavor  to  expand.  The  outer  hard 
layer  of  the  steel  lies  like  a  ring  upon  the  interior  layers, 
and  the  latter  in  their  endeavor  to  expand  make  an  effort 
to  break  the  ring  and  frequently  succeed  in  doing  so.  The 
cracks  formed  commence  on  the  surface,  and  when  once 
formed  continue  in  the  direction  of  the  centre  throughout 
the  entire  cross-section. 

From  this  phenomenon  we  learn  that  by  each  heating, 
which  in  the  interior  of  the  steel  acts  upon  layers  already 
cooled,  the  endeavor  to  expand  is  increased,  and  the  danger 
of  cracking  on  the  surface  enhanced  ;  and  the  latter  may 
even  be  first  caused  by  it. 

Cracking  may  be  prevented  by  heating  the  steel  from 
the  outside,  whereby  the  exterior  hard  layer  is  made 
tougher  and  the  change  in  form  can  more  readily  take 
place. 

The  explanations  given  above  of  course  refer  only  to  tool- 
steel  of  normal  composition,  which  can  be  well  hardened. 
Steel  less  capable  of  being  hardened  when  heated  also  suffers 
a  change  in  volume,  which,  however,  is  not  fixed  by  hard- 
ening, the  hardness  not  penetrating  to  a  sufficient  depth,  so 
that  the  hardened  layer  follows  the  re-expanding  inner 
layers. 

Manganese  exerts  a  great  influence  upon  the  change  in 
volume  of  the  steel  in  hardening,  and  under  certain  condi- 
tions prevents  it  entirely.  Ingot  steel,  still  capable  of  being 
well  hardened,  with  about  0.45  carbon  and  a  higher  con- 
tent of  manganese  (0.8  to  1.0  per  cent.)  scarcely  undergoes 
a  change  in  its  dimensions  in  hardening. 


HARDENING    OF    TOOLS.  73 

Hence  such  steel  is  used  for  tools  on  which  no  great  de- 
mands are  made  and  the  dimensions  of  which  must  not  be 
changed  by  hardening. 


IX. 

HARDENING  OF  TOOLS  WHICH  ARE  TO  BE 
HARDENED  IN  THEIR  ENTIRETY. 

FROM  what  has  been  said  in  the  previous  chapter,  it  is 
evident  that  the  changes  in  volume  caused  by  hardening 
and  fixed  by  it  are  the  immediate  cause  of  cracking.  By 
letting  down  the  steel,  i.  e.,  by  toughening  it  or  making  it 
more  viscid,  the  particles  of  its  structure  can  partially  follow 
the  changes  in  form  and  cracking  is  avoided.  This  tough- 
ening, however,  must  be  done  at  the  proper  time,  in  fact, 
already  during  hardening,  and  hence  belongs  to  the  latter 
operation. 

Below  will  be  described  the  means  by  which  failure  in 
hardening  may  be  avoided  by  letting  down. 

Before  proceeding  with  the  operation  of  hardening,  the 
hardener  should  first  of  all  form  a  clear  idea  of  the  portions 
of  the  tool  in  which  formation  of  cracks  is  to  be  feared,  and 
take  such  measures  as  may  serve  for  the  avoidance  of  them. 

As  a  general  rule  it  may  be  assumed  that  all  projecting 
parts  of  a  tool— corners,  edges,  teeth,  etc. — will  be  most 
subject  to  snapping  off  or  superficial  separation. 

Cracking  from  the  interior  is  to  be  feared  with  massive 
tools  of  large  dimensions.  If  such  tools  possess,  in  addition, 
projecting  parts  on  the  surface,  as  for  instance,  large  screw 


74  TOOL-STEEL. 

taps,  broaches,  cutters,  etc.,  the  severance  of  these  parts  is 
the  more  to  be  feared  the  larger  are  the  dimensions  of  the 
massive  portions  of  the  tools. 

By  letting  down  the  steel  on  the  surface  where  it  pos- 
sesses the  greatest  hardness,  the  particles  of  the  structure 
acquire  greater  mobility  ;  the  condition  of  greatest  rigidity 
being  destroyed.  In  consequence  of  the  greater  toughness 
or  viscidity  thereby  obtained,  a  scale-like  separation  of  por- 
tions on  the  surface  of  the  tool  is  avoided  if  letting  down 
be  effected  at  a  time  when  separation  has  not  already  taken 
place. 

As  previously  mentioned,  cracking  on  or  near  the  surface 
generally  takes  place  already  during  cooling  and  is  brought 
about  the  more  readily  the  harder  the  steel  is,  the  higher 
the  temperature  at  which  it  has  been  hardened,  and  the 
colder  the  hardening  fluid  has  been.  If,  for  instance,  a 
massive  cutter  with  many  teeth  be  hardened  in  water  and 
allowed  to  cool  only  so  far  that  when  under  water  it  can  be 
touched  with  the  hand,  a  crack  will  seldom  be  observed  on 
the  teeth.  If,  however,  it  be  immediately  returned  to  the 
cooling  bath  and  allowed  further  to  cool,  the  severance  of 
single,  and  sometimes  of  all  the  teeth  takes  place  very  rap- 
idly, and  continues  after  the  entirely  cooled  cutter  has  been 
taken  from  the  hardening  bath.  When  cracks  on  the  sur- 
face are  formed,  a  peculiar  chinking  noise  well-known  to 
experienced  hardeners  is  heard.  The  snapping  off  of  the 
teeth  of  the  cutter  is  due  to  the  fact  that  cooling  off  has 
been  continued  until  the  outermost,  hardest  layer  has  ac- 
quired the  highest  degree  of  brittleness  and  hardness,  and 
the  supply  of  heat  from  the  interior  was  no  longer  sufficient 
to  maintain  it  in  a  state  of  greatest  toughness  or  viscidity. 


HARDENING    OP    TOOLS.  75 

The  power  of  resisting  the  strain,  which  increases  in  force 
with  progressive  cooling,  becomes  less  and  is  finally  over- 
come. 

Superficial  scale-like  separations  on  tools  are  avoided  by 
interrupting  cooling  off  at  a  period  when  the  tool  is  com- 
pletely hardened  but  not  entirely  cold  (fractional  hard- 
ening). 

When  the  tool  which  is  now  allowed  slowly  to  cool,  still 
retains  sufficient  heat  in  the  interior  to  heat  the  surface  to 
a  high  degree,  it  may  completely  lose  the  hardness  pro- 
duced ;  it  becomes  soft. 

To  prevent  this,  the  partially  cooled  tool  is  not  allowed 
to  get  cold  in  the  air,  but  is  brought  into  a  fluid  which 
withdraws  the  heat  less  rapidly  than  the  hardening  fluid — 
generally  oil  or  melted  tallow — in  which  it  is  allowed 
quietly  to  cool.  However,  this  process  cannot  always  be 
relied  upon,  and  in  practice  is  reluctantly  resorted  to  if 
the  highest  degrees  of  hardness  are  positively  to  be  ob- 
tained. 

The  highest  degree  of  hardness,  however,  is  only  attain- 
able when  the  tool  is  so  completely  cooled  in  hardening 
that  actual  letting  down  from  the  interior  is  out  of  the 
question. 

By  reference  to  the  table  facing  p.  22  it  will  be  seen, 
that  the  pale  yellow  temper-color  commences  to  appear  on 
the  heated  steel  at  a  temperature  of  428°  F.  The  tool 
completely  cooled  off  and  hardened  on  the  surface  can 
therefore  without  hesitation  he  heated  from  the  outside  to 
about  the  above-mentioned  temperature  without  fear  of  an 
appreciable  loss  in  hardness. 

By  this  heating  from  the  outside,  the  rigid  hard  surface 


76  TOOL-STEEL. 

of  the  tool  acquires  a  somewhat  greater  toughness  or  viscid- 
ity and  can  more  readily  follow  the  changes  in  volume  of 
the  interior  without  separating  or  losing  in  hardness. 

This  process  is  very  frequently  applied  in  practice  by 
the  hardener  immediately  returning  the  tool,  when  nearly 
completely  cooled,  to  the  hardening  fire  and  at  the  same 
time  heating  it  to  a  low  degree  of  temperature  at  which  an 
actual  oxidation  cannot  take  place.  The  reheated  tool  is 
then  allowed  slowly  to  cool.  Great  skill  is,  however,  re- 
quired for  heating  the  steel  very  uniformly  in  the  harden- 
ing fire,  and  preventing  the  sharp  edges  and  corners  from 
being  finally  overheated.  Hence  it  is  preferred  to  reheat 
the  tool  in  hot  sand  or  hot  water  instead  of  in  the  harden- 
ing or  forge  fire. 

For  this  purpose  the  sand  in  a  vessel  is  heated  to  such  a 
degree  that  it  can  no  longer  be  touched  with  the  hand  and 
small  quantities  of  water  poured  upon  it  evaporate  without 
hissing.  The  hardened  tool  is  then  at  the  proper  time 
brought  into  the  hot  sand,  and  after  being  uniformly 
covered  with  it,  allowed  to  cool.  The  manipulation  with 
hot  water  is  safer  as  regards  the  temperature  to  be  used  in 
reheating.  The  tool  when  almost  completely  cooled  is 
quickly  plunged  in  boiling  or  highly  heated  water  and 
allowed  to  cool  in  it. 

If  the  tool  has  been  brought  too  soon  into  the  hot  water, 
i.  e.,  at  a  time  when  enough  heat  is  still  stored  in  the  in- 
terior which  in  conjunction  with  the  heat  acting  from  the 
exterior  would  suffice  to  cause  a  decrease  of  hardness,  the 
tool  is  after  a  few  minutes  returned  to  the  hardening  bath, 
again  cooled  off,  and  finally  allowed  to  cool  entirely  in  hot 
water. 


HARDENING    OP    TOOLS.  77 

The  above-described  process  for  protecting,  during  hard- 
ening, tools  which  are  to  be  hardened  in  their  entirety  from 
possible  cracking  from  the  outside  or  inside  by  partial 
letting  down  or  toughening,  can  be  recommended  for  all 
kinds  of  tools  without  regard  to  their  shape  or  size. 

In  some  cases  it  is  recommended  to  allow  the  hardened 
tool  to  remain  in  the  hardening  bath  until  it  is  entirely 
cold,  and  for  a  considerable  time  afterwards.  The  object  of 
this  process  is  to. maintain  undiminished  the  highest  attain- 
able degree  of  hardness  in  the  interior  of  the  tools.  Letting 
down  for  the  purpose  of  obtaining  greater  toughness  or 
viscidity  on  the  surface  is  then  effected  by  the  application 
of  heat  from  the  outside  to  the  tool  when  completely  cooled. 

To  be  sure  in  using  this  process  there  is  a  risk  of  the  loss 
of  the  tool.  Scale-like  separation  of  the  corners  and  edges 
frequently  takes  place,  particularly  with  the  use  of  especi- 
ally tough  steel,  though  cracking  of  the  piece  from  the 
interior  occurs  less  frequently.  The  process  finds  practical 
application  in  hardening  tools  which  work  under  especially 
high  pressure.  Large  tools,  for  instance,  rolls,  or  tools  of 
especially  complicated  form,  for  instance,  hollow  bodies, 
tubes,  etc.,  cannot  be  hardened  by  the  process  customary 
for  smaller  tools  without  fear  of  failure.  For  cooling  such 
tools  special  devices  are  required,  a  detailed  description  of 
which  will  be  given  later  on. 

The  hardening  of  tools  the  entire  surface  of  which  is  to 
be  uniformly  hard,  makes  the  greatest  demands  on  the  skill 
and  experience  of  the  hardener  and  requires  the  best  kinds 
of  appliances. 

However  in  practice  it  does  not  alone  suffice  to  pro- 
tect one's  self  from  the  loss  of  a  tool  in  hardening  by  heat- 


78 


TOOL-STEEL. 


ing  and  cooling  in  an  appropriate  manner  in  order  to  de- 
crease the  danger  of  cracking,  but  it  is  also  necessary  for 
the  designer  of  the  tool  to  take  into  consideration  the  influ- 
ence of  the  forces  which  are  formed  in  hardening  and 
directed  towards  the  destruction  of  the  tool. 

In  some  cases  almost  impossibilities  are  demanded  from 
the  hardener,  the  strangest  shapes  being,  for  instance,  given 
to  cutters  without  considering  that  the  danger  of  the  loss 
of  the  tool  in  hardening  increases  with  size  and  complicated 


form,  even  if  hardening  has  been  done  with  the  utmost 
care.  Hence,  tools  of  large  or  complicated  shapes  are,  as 
far  as  their  mode  of  application  permits,  divided  into  sev- 
eral sections,  which  when  put  together  form  the  finished 
tool.  Thus,  for  instance,  long  plane  cutters  are  made  in 

FIG.  36. 


several  short  pieces,  as  shown  in  Fig.  35.  The  cutting 
surface  is  laid  obliquely  to  the  axis  of  the  tool  so  that  the 
joint  is  not  detrimental  to  the  cleanness  of  the  work. 

With  thick  irregular  shapes,  as  shown  in  Fig.  36,  the 


HARDENING    OF    TOOLS.  79 

•danger  of  cracking  from  the  interior  in  consequence  of 
unequal  rapid  cooling  is  diminished  by  boring  out  so  as  to 
give  the  walls  of  the  tool  as  nearly  as  possible  the  same 
thickness.  In  other  cases  the  strains  in  the  interior  of  a 
tool  with  symmetrical  cross-section  are  diminished  by  bor- 
ing it  out.  Very  large  taps,  broaches,  etc.,  which  after 
hardening  readily  crack  from  the  interior  and  cool  with 
difficulty  in  consequence  of  the  heat  stored  in  the  interior, 

FIG.  37. 
Bored-ovt  Broach  ofLar$e  croK-secHon . 


-•l- -us    -. 


are  bored  through  in  the  direction  of  their  length,  as  shown 
in  Fig.  37. 

In  solid  tools  the  strains  formed  in  hardening  converge 
in  the  centre,  while  in  tools  bored  out  they  are  distributed 
upon  the  circumference  of  the  bore. 

An  enumeration  of  all  the  cases  in  which  the  danger  of 
failure  in  hardening  may  be  diminished  by  a  very  simple 
change  in  the  form  of  the  tool  is,  of  course,  out  of  the  ques- 
tion, but  it  may  be  mentioned  that  in  practice  such  cases 
are  quite  numerous. 

The  main  points  to  be  considered  in  the  construction  of 
a  tool  are  whether  its  form  is  as  simple  as  possible  and 
whether  the  projecting  portions  correspond  favorably  to  the 
bulk  of  the  tool ;  further,  whether  sharp  corners  and  edges 
are  as  much  as  possible  avoided,  and  whether  there  is  a 
gradual  transition  of  different  cross-sections. 


80  TOOL-STEEL. 

'        .         x.         •  " .  '"V 

HARDENING  OF  TOOLS   WHICH   ARE   ONLY    TO 
BE  PARTIALLY  HARDENED. 

THE  operation  of  hardening  tools  which  must  possess 
throughout  a  uniformly  hard  surface,  as  described  in  the 
previous  chapter,  presents  the  greatest  difficulties  to  the 
manufacturer  of  tools,  and  requires  considerable  skill  and 
experience. 

However,  the  greater  number  of  tools  are  only  partially 
hardened,  namely,  the  parts  which  in  use  are  subject  to 
great  wear,  while  the  other  portions  are  to  be  as  tough  as 
possible. 

With  reference  to  the  main  points  and  the  nature  of  the 
tools,  partial  hardening  may  be  divided  into  three  groups 
as  follows : 

1.  In  heating  the  tool  for  hardening,  every  portion  of  it 

which  is  to  be  hardened  may  be  heated  to  such  an 
extent  as  is  required  to  obtain  a  uniform  degree  of 
hardness,  and  the  operation  of  hardening  may  also 
be  carried  on  accordingly,  for  instance,  with  turning 
knives,  chisels,  gouges,  etc. 

2.  On  account  of  its  small  size  or  shape,  the  entire  bulk 

of  the  tool  to  be  partially  hardened  has  to  be  heated, 
but  hardening  may  be  partially  effected  as,  for  in- 
stance, with  hammers,  sledges,  small  punches,  short 
and  broad-cutting  knives,  etc. 

3.  The  tool   must  be  heated  and   hardened  all  over  to 

prevent  distortion,  partial  cracking,  etc.  The  hard- 
ness of  the  portions  of  the  tool  not  subject  to  wear  is 


HARDENING    OF    TOOLS.  81 

after  hardening  reduced  by  reheating,  for  instance, 
with  all  kinds  of  knives  (shear-knives,  wood-planing 
knives,  stamping  knives  for  paper  and  leather). 

What  has  been  said  in  reference  to  heating  tools  which 
are  to  be  hardened  all  over,  applies  also  to  partial  hard- 
ening, i.  e.<  the  steel  must  under  no  conditions  be  heated 
too  highly,  or  unequally  on  the  places  to  be  hardened. 

Heating  must  also  be  so  effected  that  the  portions  to  be 
hardened  show  a  uniform  hardening  temperature  which  in 
not  too  rapid  gradation  decreases  in  the  portions  of  the  tool 
not  to  be  hardened. 

When  a  tool  runs  to  a  thin  edge  the  latter  becomes  warm 
in  the  fire  and  is  readily  overheated  before  the  portion 
further  back  acquires  the  required  temperature.  In  this 
case  the  portion  back  of  the  edge  is  first  heated  to  a  dark 
cherry  red,  and  then  the  edge  to  the  hardening  temper- 
ature. 

If  the  portion  of  the  tool  to  be  hardened  possesses  a  small 
cross-section  running  rapidly  and 
quite  immediately  into  a  larger  FJG<  38> 

cross-section,  for  instance,  a 
punch,  Fig  38,  the  thicker  por_ 
tion  a  is  first  heated  until  it 

shows  the  proper   hardening  temperature,   and    then    the 
thinner  portion  b. 

Broad  cutters  may  in  heating  be  readily  overheated  on 
the  sharp  corners  if  not  protected  therefrom  by  occasional 
cooling  off.  Such  cooling  off,  in  case  the  corners  should 
show  a  higher  temperature  than  the  other  portions  of  the 
cutter,  is  effected  by  dabbing  them  with  a  moist  rag  or 
scattering  upon  them  a  dry  powder  consisting  of: 
6 


82  TOOL-STEEL. 

Calcined  common  salt 1  part  by  volume. 

Pulverized  hoofs 1  part  by  volume. 

Powdered  charred  leather 1  part  by  volume. 

Rye  flour 1  part  by  volume. 

If,  on  account  of  their  form,  tools  which  are  to  be  par- 
tially hardened  have  to  be  heated  all  over,  it  must  be  done 
so  that  the  portion  to  be  hardened  acquires  last  of  all  the 
proper  hardening  temperature,  the  portion  not  to  be  hard- 
ened being,  therefore,  first  exposed  to  the  higher  tempera- 
ture in  the  fire.  As  regards  tools  which  are  to  be  partially 
hardened,  it  may  be  mentioned,  that  by  cooling  them  a 
sharp  line  of  dernarkation  between  the  hardened  and  un- 
hardened  portions  should  never  be  allowed  to  form,  but 
there  should  be  a  very  gradual  transition  of  one  into  the 
other. 

If  a  bar  of  steel  be  heated  to  a  uniform  cherry-red,  and 
then  immersed  to  a  certain  depth  in  water  and  cooled  so 
that  a  sharp  line  of  demarkation  is  formed  between  the 
hardened  and  unhardened  portions,  and  an  experiment  be 
made  in  breaking  the  bar,  fracture  will  take  place  the  more 
assuredly  on  the  line  of  the  hardened  part,  the  harder  the 
steel  used. 

The  strains  on  the  sharp  boundary  of  the  hardened  por- 
tions are  sufficiently  great  to  make  such  demands  on  the 
strength  that  less  force  is  required  to  produce  fracture  along 
this  line  than  on  any  other  places  of  the  steel.  In  use,  tools 
thus  hardened,  soon  break  along  the  boundary  between  the 
hardened  and  unhardened  portions,  if  it  does  not  already 
occur  in  hardening. 

A  gradual  progress  of  hardening  is  attained  by  slowly 
moving  the  tool  up  and  down  during  cooling. 


COOLING    OF    TOOLS    IN    HARDENING.  83 

If  tools  are  to  be  hardened  so  that  there  is  a  gradual 
transition  of  the  hardened  into  the  unhardened  portions 
with  rapid  cooling,  as  is  frequently  desirable  in  the  manu- 
facture on  a  large  scale,  the  appliances  for  heating  must 
of  course  be  made  with  great  care,  so  that  abrupt  transitions 
of  temperature  do  not  occur  on  any  portion  ot  the  tool,  be- 
cause when  such  is  the  case,  partial  hardening  also  causes  a 
sharp  line  of  demarkation  between  the  hardened  and  un- 
hardened portions. 


XL 


COOLING   OF   TOOLS    IN   HARDENING   AND 
DEVICES  FOR  THIS  PURPOSE. 

THE  general  rule  for  cooling  tools  is  of  exactly  the  same 
purport  as  that  for  heating  them  for  hardening,  namely, 

Cooling  of  the  red-hot  tool  should  be  effected  so  evenly 
that  the  heat  is  uniformly  withdrawn  from  the  por- 
tion to  be  hardened. 

This  rule  seems  very  simple,  but  in  practice  it  is  not 
always  easy  to  follow  it,  because  even  by  simply  immersing 
the  red-hot  tool  in  the  hardening  fluid,  unequal  cooling 
takes  place  at  the  outset. 

While  the  tool  remains  in  the  hardening  bath,  steam  is 
formed  by  the  evaporation  of  the  fluid,  and  where  the  steam 
cannot  escape  with  sufficient  rapidity  the  tool  is  enveloped 
by  a  layer  of  it  which  prevents  uniform  hardening.  Hence, 
the  article  to  be  cooled  must  be  kept  in  constant  motion  so 
that  it  always  comes  in  contact  with  fresh  layers  of  the 

S 
UNIVERSITY 


84  TOOL-STEEL. 

hardening  fluid,  and  the  steam  evolved  can  escape  with 
greater  facility.  However,  by  this  motion  the  separate 
sides  of  the  tool  are  alternately  brought  into  more  energetic 
contact  with  the  cooling  fluid  and  also  unequally  cooled, 
the  consequence  being  that  the  tool  warps  or  cracks. 
When  the  tools  to  be  hardened  are  small,  heat  is  very 
rapidly  withdrawn  from  them  and  unequal  cooling  by  im- 
mersing and  moving  them  about  seldom  causes  warping  or 
cracking. 

When  especially  large  and  heavy  tools  are  to  be  hard- 
ened, or  tools  which  on  account  of  their  cross-section  show 
a  ready  tendency  to  warp,  they  are  not  moved  about  in  the 
hardening  fluid,  but  the  latter  is  set  in  motion.  This 
motion  may  be  a  simple  one,  when  the  hardening  fluid  acts 
from  one  side  upon  the  tool,  or  a  combined  one,  when  it 
acts  simultaneously  from  several  sides. 

Before  entering  upon  a  further  explanation  of  what  has 
to  be  observed  in  the  actual  hardening  of  tools,  attention 
may  be  drawn  to  a  very  important  fact  which  may  often 
be  noticed. 

It  frequently  happens  that  tools  which  have  been  heated 
with  the  greatest  care  are  previously  to  hardening,  exposed 
to  cooling,  and  then  hardened  when  in  a  state  of  unequal 
temperature.  As  a  rule  this  is  not  taken  into  consideration 
and  ultimate  failure  in  hardening  is  ascribed  to  entirely 
different  causes. 

Unequal  cooling  of  the  tool  immediately  before  harden- 
ing may  be  caused  by  a  sharp  draught  of  air,  and  this 
should  be  avoided  as  much  as  possible  in  the  neighborhood 
of  the  hardening  fire.  When  the  red-hot  tool  for  the  pur- 
pose of  hardening  is  brought  from  the  furnace  or  fire,  it  is 


COOLING    OF    TOOLS    IN    HARDENING.  85 

frequently  laid  upon  cold  iron  plates  or  even  upon  a  damp 
support  to  facilitate  catching  it  with  the  tongs.  The  un- 
equal cooling  thus  induced  is  frequently  the  cause  of  cracks 
being  formed. 

Catching  the  red-hot  tool  with  cold  tongs,  or  with  tongs 
wet  from  a  previous  hardening  operation,  will  almost 
alvvays  cause  the  formation  of  cracks,  especially  with  a  tool 
of  a  small  cross-section,  since  uneven  cooling  penetrates 
immediately,  the  entire  cross-section.  Such  a  tool  is  best 
heated  by  catching  it  with  the  tongs  and  heating  it  to- 
gether with  the  latter.  When  this  cannot  be  done,  the 
jaws  of  the  tongs  should  be  heated  to  a  dark  red  heat  each 
time  before  seizing  the  red-hot  tool.  Cracks  which  are 

FIG.  39. 


formed  by  uneven  cooling  from  catching  with  the  tongs, 
as  a  rule,  run  a  quite  regular  course,  they  being  formed 
either  in  the  direction  of  the  length  of  the  tool,  or  return 
in  a  curved  line  to  the  initial  point.  The  dotted  line  in 
Fig.  39  shows  the  course  of  such  a  crack  on  a  twist-drill. 

When  a  tool  which  is  to  be  hardened  is  grasped  with  the 
tongs  and  together  with  the  latter  immersed  in  the  harden- 
ing fluid,  care  should  be  taken  that  the  jaws  of  the  tongs 
come  in  contact  with  as  few  points  of  the  tool  as  possible, 
because  the  portions  of  the  latter  covered  by  the  tongs  do 
not  cool  with  sufficient  rapidity  ;  the  consequence  being 
uneven  hardness,  and  cracks  commence  to  form  •  on  the 
places  grasped  by  the  tongs.  For  catching  tools  to  be 


86 


TOOL-STEEL. 


hardened,  tongs  with  jaws  terminating  in  as  sharp  points 
or  edges  as  possible  should  be  used.  Tools  bored  through 
are  taken  up  with  a  hook  pushed  through  the  bore. 

Fig.  40  shows  a  cylindrical  revolving  knife  held  by 
tongs  properly  selected  ;  Fig.  41,  a  cutter,  and  Fig.  42,  a 
cutter  grasped  with  an  iron  hook.  On  the  other  hand, 
Fig.  43  shows  a  cutter  held  by  tongs  not  suitable  for  hard- 
ening purposes. 

In  many  cases  when  thin  flat  tools  are  to  be  partially 
hardened,  the  portions  not  to  be  hardened  are  covered 
before  cooling  with  pieces  of  sheet-iron,  etc.,  or  the  tools  are 
grasped  with  tongs,  the  jaws  of  which  are  so  shaped  as  to 


FIG.  40. 


FIG.  41. 


FIG.  42. 


FIG.  43. 


form  the  covering.  However,  cracking  and  distortion  of  the 
tool  are  frequently  caused  by  this  mode  of  partially  hard- 
ening, and  it  should  only  be  used  with  very  soft  varieties  of 
steel  which  require  merely  superficial  hardness.  When  thin 
flat  articles,  some  portions  of  which  have  been  covered, 
are  heated  and  hardened,  a  sharply  defined  boundary,  in 
accordance  with  the  extent  of  the  covering,  is  formed  be- 
tween the  covered  portions,  which  are  not  at  all  or  only 
slightly  hardened  and  the  portions  which  are  completely 
hardened.  The  thicker  the  covering  is,  the  more  sharply 


COOLING    OF    TOOLS    IN    HARDENING. 


87 


defined  this  boundary  will  be.  In  order  to  broaden  the 
transition  from  the  unhardened  to  the  hardened  portions, 
the  covering  should  be  thinner  towards  its  edge,  and  the 
latter  should  not  very  firmly  rest  upon  the  article.  How- 
ever, when  the  same  object  can  be  attained  by  another 
method,  for  instance  by  reheating  the  hardened  portions 
which  are  to  be  soft,  it  is  to  be  preferred. 

For  thick  tools  of  symmetrical  form,  unequal  hardening 
by  covering  separate  portions  is  employed  when  the  strains 
formed  in  hardening  are  to  be  dispersed  and  not  allowed  to 
converge  towards  a  centre ;  further,  when  the  zone  of 
greatest  hardness  is  to  be  limited  to  as  small  a  space  as 
possible. 

Fig.  44  represents  one-half  of  a  cutter  which  has  been 

FIG.  44. 


hardened  without  covering.  The  exterior  zone  which  has 
acquired  the  full  degree  of  hardness  is  not  hatched,  and  is 
bounded  by  the  line  a  a'.  Along  this  line  the  steel  possesses 
least  strength  and,  in  hardening,  separation  of  teeth  will 
take  place  in  accordance  with  it.  From  the  point  b  and 
the  line  c,  the  strains  act  radially  towards  the  exterior. 
When  in  hardening  the  same  cutter  is  protected  on  the  face 
by  covering  with  sheet-iron  discs  as  shown  in  Fig.  45,  cool- 
ing and  hardening  proceed  as  shown  in  the  sketch  of  the 
cross-section.  The  line  a  af  shows  the  course  of  the  bound- 


88 


TOOL-STEEL. 


ary  of  least  strength.  The  strains  disperse  themselves  in 
parallel  direction  and  reparation  of  teeth  in  the  direction  of 
their  course  does  not  so  readily  take  place.* 


FIG.  45. 


It  is  an  absolutely  necessary  provision  for  this  mode  of 
protection  that  the  covering  should  project  over  the  por- 
tions to  be  protected.  If  the  covering  were  of  a  smaller 
extent,  for  instance  as  shown  in  Fig.  46,  the  result  would 


FIG.  46. 


be  just  the  reverse  from  that  intended,  because  a  sharply 
defined  boundary  would  be  formed  between  the  hardened 
and  unhardened  portions  of  the  tool. 

The  application  of  the  above-mentioned  method  is  of  course 
very  limited,  and  depends  on  the  form  of  the  tool  as  ivell 
as  on  the  extent  of  the  surface  to  he  hardened. 
It  is  largely  employed  in   hardening  rolls  of  very  hard 

*  Beside  the  above-mentioned  strains  in  the  direction  of  the  cross-section, 
the  entire  circumference  stands  under  considerable  strain,  which  is  caused  by 
its  having  been  shortened  by  hardening,  and  by  the  pressure  of  the  inner  less 
hardened  layers  upon  the  outer  hard  layer. 


COOLING    OF    TOOLS    IN    HARDENING.  89 

steel  in  order  to  decrease  the  danger  of  cracking,  and  in 
hardening  parts  of  machines  certain  portions  of  the  surfaces 
of  which  are  to  be  hard  to  prevent  rapid  wear. 

Tools  which  by  reason  of  their  forms  or  dimensions  have 
for  the  purpose  of  hardening  to  be  heated  in  their  entirety, 
should  always  be  cooled  in  a  fluid  which  is  in  a  state  of 
motion  in  such  a  manner  that  the  surface  to  be  hardened 
is  exposed  to  a  continuous  stream. 

The  most  simple  manner  of  effecting  this  is  to  immerse 
the  red-hot  tool  in  running  water.  However,  uniform  ac- 
tion by  this  means  is  only  effected  laterally  and  hardening 
in  running  water  requires,  as  a  rule,  the  immersion  of  the 
entire  red-hot  tool,  consequently  also  cooling — hardening — 
of  the  portions  not  intended  to  be  hard.  Hardening  in 
water  running  in  a  horizontal  direction,  for  instance,  in 
gutters,  channels,  etc.,  offers  no  appreciable  advantages  as 
regards  uniformity  of  cooling,  especially  of  larger  surfaces, 
the  only  advantage  being  the  relatively  uniform  temper- 
ature of  the  water  on  account  of  the  latter  being  constantly 
renewed.  The  temperature  of  free  running  water  is  of 
course  not  absolutely  uniform,  it  depending  on  the  season 
of  the  year. 

The  mode  of  using  running  water  for  hardening  is  as 
follows :  The  water  is  conducted  into  the  vessel  to  be  used 
for  hardening  purposes,  and  the  supply  regulated  so  that 
the  temperature  remains  the  same  even  when  hardening  is 
continuously  carried  on.  Fig.  47  shows  a  simple  device 
for  the  purpose.  The  water  runs  in  at  Z  and  runs  off 
through  a  notch  A  in  the  side  of  a  barrel  which  serves  as 
the  hardening  vessel. 

For  hardening  tools,  special  advantages  are  offered  by 


• 


90 


TOOL-STEEL. 


the  employment  of  falling  water,  because  it  is  feasible 
thereby  to  expose  to  it  only  the  portions  of  the  red-hot  tool 
which  are  to  be  hardened.  The  process  of  hardening  by 
means  of  free-falling  water  is  very  simple,  it  being  only 
necessary  to  expose  the  area  to  be  hardened  to  the  action  of 
the  jet  of  water  until  completely  cooled.  The  main  point 

FIG.  47. 


in  this  process  is  that  every  portion  of  the  area  to  he  hard- 
ened is  uniformly  struck  by  the  jet  of  water.  If  the  latter 
is  not  sufficient  to  cover  uniformly  the  area  to  be  hardened, 
it  may  be  adjusted  by  moving  the  tool  about,  but  the  dan- 
ger of  defective  hardening  is  not  entirely  averted. 

With  a  plentiful  supply  of  water  the  device  shown  in 
Fig.  48  is  very  suitable  for  hardening  under  falling  water. 
The  water  is  conducted  to  the  vat  H,  which  may  be  con- 
structed of  wood,  iron,  or  brick,  through  the  conduit  L,  the 
notch  E  serving  for  the  overflow  of  the  excess  of  hardening 
water  as  well  as  for  keeping  the  latter  at  the  same  level. 
To  the  conduit  L  is  fitted  a  cock  the  discharge  opening  of 
which  is  provided  with  a  thread  to  which  may  be  screwed 
a  rose  (see  sketch  Fig.  48).  This  rose  comes  into  use  when 
the  water  flowing  from  the  cock  M  is  to  be  distributed  over 
a  larger  area.  Of  course  with  the  use  of  the  rose  the  water 
must  flow  under  a  certain  pressure.  The  tool  to  be  hard- 


COOLING    OF    TOOLS    IN    HARDENING. 


91 


ened  is  laid  upon  the  grate  R  fixed  under  the  cock  M,  and 
the  latter  being  opened,  cooling  is  continued  until  the  tool 
is  cold.  In  many  cases,  especially  when  very  hard  steel  is 
hardened  under  the  jet  of  water,  the  strains  formed  by 
hardening  have  to  be  somewhat  equalized.  For  this  pur- 
pose the  tool  is  not  allowed  to  become  entirely  cold  under 
the  jet  of  water,  but  hardening  is  interrupted  at  a  suitable 

FIG.  48. 


Gntt  above  »?/»/•  Itre/ 
R     »>»   be/o*   »tt       »* 


fommer^Hcad  Ly/nj   upon  thefrtt* 


Hardened  Sorfaoc 


//////////£////// ////////////JL 


moment  and  the  tool,  hardened  side  down,  is  laid  upon  a 
grate  extending  somewhat  below  the  surface  of  the  water, 
upon  which  it  is  allowed  completely  to  cool.  Oxidation  of 
the  hard  surface  is  prevented  by  fresh  water  running  con- 
stantly in  at  the  side  (see  sketch,  Fig.  48).  The  cock  M 
should  extend  to  the  centre  of  the  hardening  vat  and  should 
be  movable  so  that  it  can  be  turned  out  of  the  way  when 
not  in  use. 


92 


TOOL-STEEL. 


In  case  a  water  conduit  or  running  water  is  not  avail- 
able, the  device  shown  in  Fig.  49  may  serve  the  purpose. 

It  is,  of  course,  only  intended  for  occasional  hardening 
under  the  water-jet,  or  when  for  want  of  water  flowing 
under  pressure,  hardening  is  to  be  effected  in  an  ascending 
water-jet. 

The  very  simple  device  consists  of  two  vessels  H H, 
arranged  one  above  the  other.  From  the  upper  vessel  //, 
a  pipe  R  conducts  the  water  to  the  cock  M.  The  pipe  R 

FIG.  49. 


FIG.  50. 


shown  in  the  same  sketch  extends  to  the  bottom  of  the 
vessel  H  and  is  then  bent  upward,  thus  causing  the  jet  of 
water  to  ascend.  When  hardening  is  to  be  effected  under 
an  ascending  water-jet  and  there  is  at  hand  neither  a  water 
conduit  nor  other  device  for  producing  a  water-jet,  a  funnel 
constantly  kept  full  by  pouring  in  it  a  uniform  supply  of 
water  may  be  used.  Still  more  convenient  is  the  use  of  a 
siphon  made  by  bending  a  piece  of  gas  pipe.  For  use  the 
siphon  is  filled  with  water  and  brought  into  the  position 


COOLING    OF    TOOLS    IN    HARDENING.  93 

shown  in  Fig.  50.  As  the  water  flows  from  the  siphon 
with  but  slight  force,  this  device,  of  course,  is  available  only 
for  small  areas. 

The  object  of  hardening  in  an  ascending  water-jet  is  the 
same  as  in  a  falling  water-jet,  and  its  use  is  preferred  if  per- 
mitted by  the  form  of  the  tool  or  the  area  to  be  hardened. 

A  falling  and  an  ascending  water-jet  are  simultaneously 
employed  in  hardening  tools  which  are  to  possess  the  same 
degree  of  hardness  on  two  opposite  sides,  and  one  end  of 
which,  by  reason  of  their  short  length,  cannot  be  heated 
without  the  heat  being  at  the  same  time  transmitted  to  the 
other  end,  for  instance,  pivots,  short  hammers,  sledges,  etc. 

While  tool-areas  may  under  all  conditions  be  hardened 
by  means  of  a  falling  water-jet — and  in  some  cases  must 
even  be  thus  hardened — the  employment  of  an  ascending 
water-jet  depends  on  the  form  of  the  area  to  be  hardened. 

When  the  area  to  be  hardened  is  level  or  has  elevations 
or  bulges  out  otherwise,  hardening  may  be  effected  with  an 
ascending,  as  well  as  a  falling,  water-jet,  but  the  former 
method  is  to  be  preferred,  since  greater  uniformity  of  hard- 
ness can  be  attained  with  it.  If,  however,  the  area  to  be 
hardened  has  depressions,  or  curves  inwardly,  hardening 
with  a  falling  water-jet  is  the  only  method  available.  The 
vapors  formed  in  cooling  with  an  ascending  water-jet  can- 
not immediately  escape,  and  being  constantly  reformed, 
prevent  contact  of  the  water  with  the  steel  so  that  harden- 
ing is  not  effected  and  the  depressions  to  be  hardened  re- 
main soft.  The  device  for  hardening  in  an  ascending 
water-jet  is  shown  in  Fig.  51.  The  supply  pipe,  R,  is 
placed  in  the  hardening  vessel,  H.  The  supply  pipe  ter- 
minates below  the  water-level;  and  the  water  flowing  from 


94 


TOOL-STEEL. 


it  carries  along  quantities  of  surrounding  water  and  con- 
veys them  to  the  area  to  be  hardened.  For  the  support  of 
the  tool,  W,  to  be  hardened,  a  grate,  R,  extending  below 
the  surface  of  the  water,  is  fitted  to  the  hardening  vessel 
(see  Fig.  51).  When  it  is  not  feasible  to  support  the  tool 
upon  the  grate,  for  fear  that  the  area  to  be  hardened  may 


FIG.  51. 


FIG.  52. 


remain  soft  on  the  places  which  come  in  contact  with  the 
grate,  it  must  be  held  with  the  tongs  Z,  and  suspended  free, 
as  shown  in  Fig.  52.  The  tool  to  be  hardened  remains 
exposed  to  the  ascending  water-jet  until  it  is  cold,  it  being, 
of  course,  immersed  to  a  sufficient  depth.  The  more  vigor- 
ous the  flow  of  water  is,  the  better  the  hardening  will  turn 
out. 

For  tools,  the  entire  bulk  of  which  is  to  be  hardened,  but 
which  are  of  such  large  dimensions  as  to  make  even  cool- 
ing by  moving  them  in  the  hardening  water  no  longer 
possible,  special  devices  are  required  for  the  uniform  con- 


COOLING    OF    TOOLS    IN    HARDENING.  95 

veyance  of  the  hardening  fluid  from  every  side  to  the  tool. 
A  brief  description  of  such  devices  for  hardening  balls  and 
rolls  will  be  found  in  the  Appendix. 

The  method  of  hardening  by  means  of  a  jet  may  also  be 
employed,  if  the  operation  of  hardening,  as  is  customary  in 
some  factories,  is  not  effected  in  pure  water,  but  in  a  large 
reservoir  which  contains  a  sufficient  quantity  of  water 
compounded  with  salts  or  acids  to  allow  of  a  large  number 
of  tools  to  be  hardened  without  its  temperature  being  essen- 
tially raised.  To  be  sure  special  small  pumps  are  then 
required,  which  for  occasional  use  may  be  worked  by  hand 
while  for  continuous  working  power  is  required.  The  ad- 
vantage of  the  use  of  such  pumps  is  that  the  lower  cooler 
layers  of  the  hardening  bath  are  brought  to  the  surface, 
the  temperature  of  the  bath  being  thus  equalized. 

Hollow  bodies  which  are  to  be  hardened  inside,  or  inside 
and  outside,  require  special  devices  so  that  cooling  may 
take  place  without  uneven  hardening  being  caused  by  the 
development  of  steam. 

Tools,  entirely  bored  through  or  hollow,  are  cooled  by 
conducting  a  powerful  jet  of  water  through  the  interior. 
If  the  surface  is  also  to  be  hardened  it  must  be  cooled  by  a 
simultaneously  acting  water  jet. 

Fig.  53  shows  the  operation  of  hardening  from  the  inside, 
and  Fig.  54  from  the  outside  and  inside.  These  devices 
require  small  power  plants. 

The  hollow  body  H  is  placed  between  two  pipes,  a  b, 
Fig.  53.  The  pipe  b  is  fitted  movable  to  the  pipe  c  so  that 
the  hollow  body  H  can  be  firmly  wedged  between  the  two 
pipes.  A  supply  cock  being  at  the  same  time  opened, 
water  under  high  pressure  enters  and  in  passing  through 
the  hollow  body  hardens  its  walls. 


96 


TOOL-STEEL. 


Fig.  54  shows  the  hollow  body  also  surrounded  by  a 
movable  pipe  d.  By  closing  the  pipes  b,  c  and  d,  the  water 
flows  through  between  them  and  hardens  the  surface  and 
interior  of  the  hollow  body.  In  place  of  the  additional 
pipe  d,  the  surface  may  also  be  cooled  by  direct-acting 
roses. 

Cooling  the  interior  of  a  hollow  body  which  is  not  en- 


FIG.  53. 


FIG.  54. 


FIG.  55. 


tirely  perforated,  presents  greater  difficulties,  and  the  more 
so  the  narrower  and  deeper  the  opening  is.  Hardening  is 
then  effected  by  the  direct  introduction  of  as  powerful  a  jet 
of  water  as  possible.  If  the  size  of  the  aperture  allows  of 
the  introduction  of  a  pipe,  one  end  of  which,  corresponding 
to  the  depth  of  the  aperture,  is  provided  with  numerous 
small  holes,  even  hardening  is  readily  obtained  with  a 
powerful  pressure  of  water  (see  Fig.  55). 


LIQUIDS    USED    IN    QUENCHING    STEEL.  9T 

XII. 

LIQUIDS  USED  IN  QUENCHING  STEEL. 
1.   PURE  WATER. 

FOR  quenching  steel  for  the  purpose  of  hardening,  pure 
water  is  mostly  employed,  and  the  colder  it  is  the  more  in- 
tense the  hardening  will  be,  and  the  less  so  the  warmer 
it  is. 

The  most  suitable  temperature  of  the  hardening  water 
lies  between  60°  and  72°  F.  Colder  water  will  not  appre- 
ciably increase  the  hardening  effect,  but  decreases  the 
toughness  of  the  steel,  the  latter  becoming  very  brittle. 

It  may  be  laid  down  as  a  rule  that  the  larger  the  cross- 
section  of  the  tool  to  be  hardened,  the  lower  the  tempera- 
ture of  the  water  must  be.  For  large  tools  a  temperature 
of  over  65°  F.  should  not  be  used.  Small,  especially  thin, 
tools  will  take  sufficient  hardness  at  a  temperature  of  the 
bath  of  about  86°  to  95°  F.  The  temperature  of  the  hard- 
ening water  must  also  be  chosen  in  accordance  with  the 
form  and  size  of  the  tool,  as  well  as  the  degree  of  hardness 
desired. 

Chemically  pure  water,  i.  e.  water  which  does  not  contain 
other  substances,  does  not  exist  in  nature,  and  its  chemical 
composition  varies  very  much,  it  containing  soluble  and  in- 
soluble mineral  salts  and  acids  in  a  state  of  minute  division. 

Many  salts  and  acids  increase  the  heat-conducting  power 

of  water  and  hence  bring  about  more  intense  hardening, 

while  earths  and  other  mineral  substances  in  the  water  have 

a  detrimental  effect  in  this  respect.  It  is  for  this  reason  that 

7 


98  TOOL-STEEL. 

pure  well  or  spring  water  which  chiefly  contains  acids  and 
carbonates  in  solution  will  harden  more  sharply  than  river 
water  (especially  when  turbid)  or  water  containing  lime. 

In  order  to  lessen  the  too  intense  hardening  effect  of  well 
or  spring  water,  some  soda  or  potash  may  be  dissolved  in 
it ;  and  to  impart  better  hardening  qualities  to  river  water, 
it  is  mixed  with  small  quantities  of  acids  (hydrochloric  acid, 
sulphuric  acid,  vinegar,  etc.).  Experienced  hardeners  place 
great  value  upon  the  favorable  effect  of  hardening  water 
which  has  been  used  for  some  time,  and  are  very  unwilling 
to  renew  it,  because  it  is  claimed  to  improve  in  quality, 
i.  e.,  it  hardens  well  and  mild.  The  reason  for  this  has  to 
be  found  in  the  fact  that  fine  particles  of  undissolved  ad- 
mixtures gradually  separate  on  their  own  account  and  sink 
to  the  bottom,  while  by  the  action  of  the  hot  steel  which  is 
plunged  into  the  water,  soluble  substances  are  gradually 
removed  by  evaporation  as  well  as  by  conversion  into  in- 
soluble substances,  the  latter  being  partially  precipitated 
upon  the  surface  of  the  steel.  Hardening  water  which  has 
been  used  for  some  time  will  finally  get  into  such  a  condi 
tion  that  the  unintentional  admixtures  have  become  harm- 
less, and  hardening  in  it  always  yields  uniform  results. 

If  this  condition  is  to  be  brought  about  from  the  start, 
the  water  should  be  boiled  before  its  being  used  for  harden- 
ing, or  it  may,  so  to  say,  be  sterilized  by  quenching  in  it 
larger  quantities  of  hot  pieces  of  iron. 

2.  HARDENING  WATER  MIXED  WITH  SOLUBLE 
CONSTITUENTS. 

Soluble  admixtures,  as  previously  mentioned,  exert  great 
influence  upon  the  action  of  the  hardening  water,  their 


LIQUIDS    USED    IN    QUENCHING    STEEL.  99 

effect  being  either  an  intensifying  one,  if  the  heat-conduct- 
ing power  of  the  water  is  increased,  or  a  moderating  and 
retarding  one,  if  the  heat-conducting  power  of  the  water  is 
decreased,  or  the  boiling  point  is  essentially  lowered. 

Common  salt  is  mostly  used  as  a  soluble  admixture  for 
increasing  the  heat-conducting  power.  It  is  dissolved  in 
varying  proportions  by  weight,  though  generally  a  saturated 
solution  of  it  is  used.  The  latter  may  be  recommended 
whenever  tools  of  complicated  shape  which  are  to  possess 
great  hardness  are  to  be  hardened  in  large  numbers  or  in 
rapid  succession. 

In  using  such  cooling  fluid,  it  must  be  borne  in  mind 
that  the  bath  must  be  of  sufficient  volume  so  that  its  tem- 
perature is  not  essentially  raised  by  continuous  hardening. 
A  vessel  of  as  large  a  size  as  possible  should  therefore  be 
selected  for  the  reception  of  the  bath,  and  it  is  better  to  use 
a  shallow  vessel  of  large  diameter  than  a  narrow  and 
deep  one. 

Soda  (carbonate  of  soda)  and  sal  ammoniac  dissolved  in 
water  do  not  produce  such  an  intense  effect  as  common 
salt;  but  though  they  are  more  seldom  used  they  are  excel- 
lent admixtures  to  hardening  water,  particularly  for  compli- 
cated tools,  especially  for  cutters,  a  superficial  separation  of 
some  parts  of  which  may  be  feared. 

Acids  in  particular  intensify  the  action  of  the  hardening 
water  in  a  much  higher  degree  than  common  salt.  They 
may  be  added  in  quantities  of  up  to  2  per  cent.,  sometimes 
in  combination  with  salts.  Organic  acids  (acetic,  citric 
acids)  produce  a  milder  effect  than  mineral  acids  (hydro- 
chloric, nitric  and  sulphuric  acids). 

Acidulated  water  is  used  for  tools  which  are  to  possess 


100  TOOL-STEEL. 

the  highest  attainable  degree  of  hardness  (cutters  for  work- 
ing articles  of  special  hardness),  or  for  giving  a  surface  of 
sufficient  hardness  to  steel  which  does  not  possess  good 
hardening  qualities. 

Alcohol  lowers  the  boiling  point  of  water  and,  when  the 
latter  comes  in  contact  with  the  hot  tool,  causes  such  an 
energetic  evaporation  that  hardening  is  more  or  less  re- 
tarded according  to  the  strength  of  the  mixture.  Water 
which  contains  a  large  proportion  of  alcohol  does  not 
harden  at  all. 

Soap.  Soap  water  does  not  harden  steel,  and  this  prop- 
erty is  made  use  of  for  rapidly  quenching  steel  when  the 
latter  is  not  to  be  sufficiently  hardened  by  cooling.  When 
some  parts  of  a  tool  which  has  been  entirely  hardened  are 
to  be  made  soft,  they  are  brought  to  a  red  heat  and  cooled 
in  soap  water  (tangs  of  files,  knives,  sabres,  saws,  etc.). 

Soluble  admixtures  of  organic  nature  retard  hardening 
more  or  less  according  to  the  proportion  of  admixture,  and 
hence  modify  the  action  of  pure  water.  In  practice  they 
are  rarely  used  and  then  only  in  small  quantities,  for  in- 
stance, milk,  sour  beer,  etc. 

3.  HARDENING  WATER  MIXED  WITH  INSOLUBLE  CON- 
STITUENTS. 

Such  water  is  frequently  used  for  hardening  especially 
complicated  tools  to  protect  them  against  cracks.  For  its 
preparation,  lime  in  the  form  of  milk  of  lime  is  chiefly  em- 
ployed, clay  or  loam  being  more  seldom  used.  Such  water 
has  a  more  or  less  retarding  effect  according  to  the  strength 
of  the  mixture.  The  admixed  constituent  being  intimately 
incorporated  with  the  water,  is  precipitated  upon  the  hot 


LIQUIDS    USED    IN    QUENCHING    STEEL.  101 

steel  when  the  latter  is  plunged  into  the  bath,  and  forms  upon 
it  a  thin  layer  which  prevents  direct  contact  of  the  steel  with 
the  hardening  water.  Cooling  thus  takes  place  more  slowly, 
and  by  reason  of  the  retarding  effect,  the  hardening  is  less 
intense  in  character. 

4.  HARDENING  WATER  MIXED  WITH  OILS  OR  FATS. 

Oils  and  fats  harden  with  considerably  less  intensity 
than  water.  The  degree  of  hardness  obtained  with  them  is 
the  less  the  larger  the  cross-section  of  the  tool,  and  also  the 
more  viscid  the  oil  or  fat  used.  When  a  tool  is  to  be  given 
a  higher  degree  of  hardness  than  is  possible  with  oil  or  fat 
alone,  the  surface  of  the  water  is  coated  with  a  layer  of  it 
and  the  tool  plunged  through  it  in  the  water  below.  The 
tool  is  thereby  less  rapidly  cooled  at  the  first  stage,  as  it 
has  become  coated  with  a  skin  of  fat  toughened  by  the  heat 
which  retards  the  further  cooling  in  the  water  below.  The 
thicker  the  layer  of  fat  or  oil  upon  the  water  is  and  the  more 
slowly  the  tool  is  plunged  through  it  the  less  the  degree  of 
hardness  will  be.  For  hardening  cutting  tools  which  are 
to  hold  their  edges  when  employed  upon  hard  materials, 
the  use  of  water  covered  with  oil  or  fat  requires  consider- 
able experience  and  great  skill  if  uniformly  good  results 
are  to  be  obtained.  For  such  tools  which  are  to  be  hard- 
ened all  over,  the  use  of  milk  of  lime  or  the  mode  of  hard- 
ening described  on  p.  76  is  to  be  preferred.  On  the  other 
hand,  tools  which  must  possess  a  tougher  degree  of  hard- 
ness, for  instance,  cutters  for  wood,  disc  knives,  circular 
shear  knives,  etc.,  may  be  hardened  to  advantage  in  water 
covered  with  a  layer  of  oil. 


102  TOOL-STEEL. 

5.  OILS  AND  FATS. 

Oils  and  fats,  as  previously  mentioned,  possess,  according 
to  their  consistency,  less  hardening  power  than  water.  The 
hardness  produced  by  them  is  mild  with  great  toughness. 

Thin  tools,  which  readily  crack  during  the  process  of 
hardening  and  which  do  not  require  the  highest  attainable 
degree  of  hardness,  are  hardened  in  oil  or  fat.  Of  the  oils, 
petroleum  hardens  with  the  greatest  intensity  ;  next  glycer- 
ine, which  heretofore  has  not  been  sufficiently  appreciated 
as  a  hardening  fluid ;  then  light  mineral  oils,  and  finally 
viscid  vegetable  oils,  for  instance,  linseed  oil. 

Amongst  fats,  melted  tallow  and  train  oil  are  most  fre- 
quently used.  A  somewhat  higher  degree  of  hardness  is 
obtained  in  melted  tallow  than  in  oils. 

In  using  fat  or  oil  for  hardening,  it  should  be  borne  in 
mind  that  a  sufficient  quantity  of  it  must  be  employed  to 
allow  of  the  article  to  be  hardened  to  be  vigorously  moved 
in  the  bath  during  cooling,  the  same  as  in  water,  and  that 
no  rise  in  the  temperature  takes  place  during  the  operation 
of  hardening.  Too  small  a  quantity  of  oil  or  fat  is,  as  a 
rule,  employed  in  practice,  and  non-success  in  hardening  is 
then  put  down  to  the  bad  hardening  qualities  of  the  oil  or  fat. 

6.  METALS. 

Mercury  of  all  the  metals  possesses  the  greatest  power  of 
conducting  heat  and  exerts  the  most  energetic  hardening 
effect.  It  is,  however,  seldom  used  and  then  only  for  hard- 
ening very  small  tools.  It  readily  volatilizes  and  for  hard- 
ening larger  tools  would  have  to  be  employed  in  consider- 
able quantities.  The  high  price  of  the  metal  and  the  losses 
in  hardening  by  volatilization  are  out  of  all  proportion  to 


LIQUIDS    USED    IN    QUENCHING    STEEL.  103 

the  advantages  derived  from  its  use.  The  vapors  formed 
in  hardening  by  the  volatilization  of  mercury  are  of  the 
same  poisonous  nature  as  the  metal  itself. 

Tin,  zinc  and  lead  and  their  alloys  in  a  melted  state  may 
also  be  used  as  cooling  agents.  However,  their  melting 
points  lie  so  high  that  actual  hardening  in  them  does  not 
take  place  to  the  same  extent  as  in  the  previously-described 
cooling  agents.  The  properties  of  steel  cooled  in  melted 
metals  also  undergo  a  change,  its  strength  being  considerably 
increased,  and  it  becomes  so  hard  that  it  can  be  worked 
only  with  difficulty  or  not  at  all.  It  possesses,  however, 
but  little  cutting  power.  Its  elasticity  is  also  increased. 

The  hardness  of  the  steel  is  still  further  increased  if  the 
tool  after  having  been  immersed  for  a  short  time  (J  to  2 
minutes  according  to  its  cross-section)  in  the  melted  metal, 
is  very  rapidly  cooled  in  water. 

This  process  of  hardening  is  suitable  for  springs  as  well 
as  tools  to  be  used  for  working  soft  materials,  and  to  which 
the  necessary  tough  hardness  aud  cutting  power  are  to  -be 
given  without  first  tempering  them  after  hardening,  as  is 
frequently  desired  in  manufacturing  on  a  large  scale. 
Further,  for  giving  the  necessary  properties  to  machine 
parts  subject  to  great  demands  as  regards  strength  and 
wear. 

In  using  melted  metals  it  is  of  importance  that  the  same 
degree  of  temperature  be  constantly  maintained.  Hence 
adequate  quantities  of  them  must  be  used,  proper  heating 
devices  provided,  and  the  temperature  tested  with  a  pyro- 
meter. 

Further  details,  especially  as  regards  the  devices  em- 
ployed in  the  manufacture  of  tools  on  a  large  scale,  would 
carry  us  too  far. 


104  TOOL-STEEL. 

7.  GASEOUS  COOLING  AGENTS. 

Tools  of  small  cross-sections  may  be  hardened  by  a  sbarp 
cold  current  of  air.  However,  the  use  of  air  or  gases  for 
hardening  is  a  very  limited  one,  and  not  very  reliable  in 
practice.  For  hardening  of  tools  in  general  it  is  of  no  im- 
portance. 

8.  SOLID  BODIES  AS  COOLING  AGENTS. 

Solid  bodies  of  good  heat-conducting  power  may  find 
practical  application  for  hardening  very  thin  tools.  Pieces 
of  wood  thoroughly  saturated  with  water  between  which 
the  thin  tool  is  laid  for  the  purpose  of  hardening  are  seldom 
used,  but  hardening  is  more  frequently  effected,  especially 
in  the  manufacture  of  saws,  between  iron  plates  which  are 
constantly  cooled  by  an  uninterrupted  stream  of  water. 
The  tools  while  between  the  iron  plates  being  also  subjected 
to  pressure,  this  method  of  hardening  is  also  termed  "  hard- 
ening by  pressure."  It  is  especially  applicable  to  the  con- 
tinuous hardening  of  band-steel,  and  to  the  manufacture  on 
a  large  scale  of  thin  tools  which  are  to  acquire  during  the 
operation  of  hardening  a  tough  serviceable  degree  of  hard- 
ness. 

Moist  sand  and  clay  also  effect  hardening,  but  it  is  diffi- 
cult to  obtain  an  even  hardness  by  their  use. 

The  cooling  agents  described  above  may,  of  course,  be  used 
in  any  combination  desired  by  effecting  cooling  in  succes- 
sion in  two,  or  more  seldom  in  three,  fluids  differing  in 
action.  The  process  most  commonly  employed  is  to  harden 
in  water  until  all  glow  has  disappeared  and  subsequently 
allowing  to  cool  completely  in  oil  or  hot  water. 

By  frequently  repeated  experiments  regarding  the  cutting 


LIQUIDS    USED    IN    QUENCHING    STEEL.  105 

power  of  medium  hard  tool-steel  hardened  in  various  cool- 
ing agents,  the  following  results  were  obtained  in  Bismarck- 
huette : 

Steel  with  1  per  cent,  carbon. 

Hardened  in  oil,  efficiency  attained 100 

Hardened  in  tallow,  efficiency  attained 108 

Hardened  in  pure  water  of  65°  F.,  efficiency  attained 133 

Hardened  in  water  with  1  per  cent,  sulphuric  acid,  efficiency  attained  ...  140 

From  the  relative  proportions  of  these  figures,  a  conclu- 
sion may  be  drawn  as  to  the  effect  of  the  different  harden- 
ing fluids  used. 


XIII. 

TEMPERING  OF  HARDENED  STEEL  AND 
DEVICES  FOR  THIS  PURPOSE. 

THE  main  points  in  regard  to  tempering  of  steel  have 
been  referred  to  on  p.  22,  and  the  table  found  there. 

Tempering  may  be  effected  in  either  one  of  three  ways, 
namely  : 

1.  By  not  allowing  the  hardened  steel  to  cool  entirely, 

but  to  effect  tempering  by  utilizing  the  heat  present 
in  the  interior  of  the  tool  or  in  a  portion  of  it,  as  it 
progresses  towards  the  hardened  part. 

2.  Cooling  off  the  tool  entirely  in  hardening,  and  effect- 

ing tempering  from  the  outside. 

3.  By  tempering  the  tool  from  the  interior  and  assisting 

the  progress  of  the  heat  from  the  exterior. 
Tempering  from  the  interior  is  effected  with  all  kinds  of 


106  TOOL-STEEL. 

tools  which  have  been  partially  hardened  and  in  which  the- 
heat  stored  back  of,  or  inside,  the  hardened  portions  is 
allowed  to  progress  towards  them,  for  instance,  turning 
knives,  hand  chisels,  hot  and  cold  chisels,  milling  toolsr 
drills,  tools  for  working  stone,  etc.,  or  swages,  cutters, 
hammers,  etc. 

To  be  able  to  recognize  the  advance  of  the  heat  by  the 
progression  of  the  temper  colors,  the  hardened  tool  is- 
rubbed  bright,  and  should  the  heat  advance  unevenly,  the 
respective  portion  is  cooled  by  immersion  for  a  short  time 
in  water. 

When  the  tool  shows  the  desired  temper  color,  it  i& 
gradually  cooled  by  being  repeatedly  plunged  for  a  short 
time  in  water. 

To  impart  special  toughness  to  a  tool  which  in  use  is  ex- 
posed to  shock  and  blow,  it  may  be  repeatedly  tempered  by 
rubbing  off  the  first  temper  color  and  again  producing  it- 
For  cutting  tools  this  method  may  unhesitatingly  be  re- 
commended especially  with  the  use  of  harder  steel  and 
when  the  tools  in  use  are  exposed  to  rebounding  blows,  as, 
for  instance,  hot  and  cold  chisels,  which  in  notching  railsr 
beams,  etc.,  are  subject  to  vigorous  blows  with  heavy  ham- 
mers ;  further,  riveting  punches  and  different  tools  used  in> 
structural  work.  Tools  to  be  partially  hardened,  which 
have  been  cooled  too  far  back  of  the  edges,  snap  readily 
after  having  been  tempered,  in  consequence  of  some  por- 
tions of  them  not  possessing  a  sufficient  degree  of  toughness, 
especially  if  the  cutting  parts  work  under  high  pressure,, 
for  instance  turning  knives,  or  are  subjected  to  shock  and 
blow  (chisels,  drills,  etc.). 

When  tools  partially  to  be  hardened  have  not  been  hard- 


LIQUIDS    USED    IN    QUENCHING    STEEL.  107 

ened  far  enough  back  of  the  edges,  they  possess  an  insuffi- 
cient degree  of  hardness,  and  the  operation  has  to  be  re- 
peated. Tools  which  show  the  required  degree  of  hardness 
only  on  the  edges  crack  readily  in  use  when  subject  to  pres- 
sure and  shock,  the  cracks  running  in  a  perpendicular 
direction  to  the  edges.  The  material  lying  immediately 
back  of  the  edge,  and  which  is  mostly  of  a  smaller  cross- 
section,  is  upset  and  the  hardened  edge  tears  in  consequence 
of  not  possessing  sufficient  toughness 
to  follow  the  change  in  form. 

The  progression  of  such  cracks  R  is 
sketched  in  Fig.  56. 

Tools  which  have  been  entirely 
hardened  are  seldom  tempered  from 
the  interior,  the  process  being  as 
follows : 

The  tool,  according  to  its  thickness, 

is  cooled  only  long  enough  for  the  surface  to  become  cold, 
and  so  that  sufficient  heat  remains  stored  in  the  interior 
which,  in  its  progress  toward  the  exterior,  causes  the  previ- 
ously hardened  surface  to  be  tempered. 

However,  since  by  this  procees  the  heat  advancing  from 
the  interior  does  not,  as  a  rule,  arrive  at  the  same  time  at 
all  portions  of  the  surface,  the  result  will  be  an  uneven  de- 
gree of  tempering,  and  is  difficult  to  judge  by  the  progres- 
sion of  the  temper-color,  because  in  the  short  space  of  time 
at  the  disposal  of  the  workman  it  is  generally  impossible  to 
brighten  every  portion  of  the  hardened  tool. 

If  tools  are  hardened  in  water  and  then  allowed  to  cool 
in  oil,  tempering  from  the  interior  results  very  uniformly, 
because  the  surrounding  oil  cools  off  the  portions  where  the 
heat  may  advance  too  energetically. 


10&  TOOL-STEEL. 

It  must,  however,  be  borne  in  mind  that  frequently  the 
heat  does  not  advance  with  sufficient  rapidity  from  the  in- 
terior to  increase  at  the  proper  time  the  toughness  of  the 
hardened  steel  along  the  line  of  least  strength — between 
the  hard  shell  and  the  mild  hard  core.  It  may  then 
happen  that  a  severance  of  the  hardened  surface,  or  por- 
tions of  it,  results  before  tempering  is  effected  ;  the  water 
in  this  case  having  cooled  the  tool  too  much  previously  to 
its  having  been  brought  into  the  oil. 

This  drawback  may  be  obviated  by  assisting  tempering 
from  the  interior  by  simultaneous  heating  from  the  outside, 
as  described  on  page  76.  Cooling  can  then  be  effected  to  a 
sufficient  depth  to  prevent  softening  by  subsequent  letting- 
down,  and  the  surface  thus  protected  from  cracks. 

Tools  thus  tempered  are,  however,  mostly  used  with  the 
full  degree  of  hardness  attained  without  softening  by  fur- 
ther tempering  from  the  outside. 

Attention  may  here  be  drawn  to  an  error  which  is  fre- 
quently committed.  In  completely  cooling  hardened  and 
tempered  tools  they  should  be  uniformly  surrounded  by  the 
cooling  fluid,  whether  the  latter  be  oil  or  water.  A  mis- 
take is  frequently  made  in  laying  the  hardened  tool  for  the 
purpose  of  cooling  upon  the  bottom  of  the  vessel  containing 
the  cooling  fluid.  On  the  place  of  contact  between  the  side 
of  the  vessel  and  the  tool,  the  latter,  for  reasons  which  can 
be  readily  understood,  becomes  softer  than  in  other  places. 
Hence  the  tool  should  be  suspended  in  the  fluid. 

Tools  of  small  cross-sections  which  cannot  be  tempered 
during  the  hardening  operation  are  hardened  entirely,  and 
immediately  after  this  operation  are  brought  into  hot  water, 
or  somewhat  reheated  in  hot  sand,  to  avoid  the  formation 
of  cracks  after  hardening. 


LIQUIDS    USED    IN    QUENCHING    STEEL.  109 

Tempering  of  hardened  tools  may  also  be  effected  over  a 
moderately  hot  charcoal  fire,  upon  hot  sand,  or  in  molten 
metals,  etc. 

In  tempering  from  the  outside  it  must  be  borne  in  mind 
that,  by  reason  of  their  slighter  thickness,  projecting  por- 
tions of  tools,  cutters,  etc.,  may  be  readily  heated  too  much 
and  lose  more  hardness  than  originally  intended.  Hence, 
tempering  should  not  be  undertaken  at  a  greater  heat  than 
necessary  for  bringing  out  the  temper  color. 

A  very  uneven  appearance  of  the  temper  color  is  an  in- 
dication of  too  rapid  or  uneven  heating.  In  handling 
tools  with  long  edges  the  temper  color  frequently  does  not 
progress  with  uniformity  in  consequence  of  uneven  heating. 
The  portions  which  have  become  heated  too  soon  are  then 
cooled  off  with  moist  rags  or  by  sprinkling  with  water  until 
the  temper  color  has  progressed  with  uniformity  in  the 
other  portions. 

Longer  tools,  one  end  of  which  is  to  be  hard  while  the 
hardness  is  gradually  to  decrease  towards  the  outer  end,  are 
tempered  by  heating  very  slowly  the  end  which  is  to  be 
softer.  The  temper  colors  then  appear  at  longer  intervals, 
and,  as  the  heat  spreads,  can  gradually  progress  towards 
the  outer  end  of  the  tool. 

The  tempering  of  tools  requires  above  all  uniform  heat- 
ing, just  the  same  as  in  hardening.  The  degree  of  heat 
attained  can,  however,  be  readily  judged  by  the  progression 
of  the  temper  colors,  and  hence  great  attention  rather  than 
skill  is  required  for  the  operation. 

The  space  of  time  in  which  tempering  results  is  also  of    (^S 
great  influence  upon  the  degree  of  toughness  attained  by 
the  steel.     The  more  slowly  tempering  is  effected,  the  more 


110  TOOL-STEEL. 

evenly  the  heat  will  be  distributed  over  the  entire  cross 
section  of  the  tool,  and  the  greater  the  degree  of  toughness 
will  be  which  the  tool  acquires. 

As  will  be  seen  from  Table  II.  (facing  p.  22),  with 
rapid  heating  the  yellow  temper  color  appears  when  the 
tool  has  acquired  a  temperature  of  442.4°  F.  By  exposing 
the  tool  for  a  longer  time  to  this  temperature  every  temper 
color  up  to  dark  blue  appears  one  after  the  other  without 
the  tool  having  been  heated  to  a  higher  temperature.  The 
smaller  the  cross  section  of  a  tool  is,  the  more  rapidly  the 
temper  colors  appear. 

A  similar  phenomenon  may  be  observed  when  hardened 
tools  are  for  some  time  laid  in  boiling  water,  their  tough- 
ness being  thereby  materially  increased  while  their  hard- 
ness is  reduced. 

This  phenomenon  is  of  practical  importance  when  tools 
are  to  be  tempered  in  molten  metals,  because  with  the  use 
of  one  and  the  same  bath  of  fixed  temperature  different 
degrees  of  toughness  and  hardness  can  be  obtained,  accord- 
ing to  the  length  of  time  the  bath  is  allowed  to  act.  The 
metal  bath  must  of  course  be  provided  with  a  pyrometer, 
and  the  duration  of  immersion  accurately  regulated. 

This  process  is  practically  applied  in  manufacturing  on  a 
large  scale,  especially  in  tempering  the  back  portions  of 
projectiles,  etc. 

Springs  are  in  many  cases  tempered  by  what  is  termed 
blazing  off  with  oil.  The  hardened  spring  is  brushed  over 
with  oil  and  heated  until  the  oil  inflames  and  burns  off. 
In  manufacturing  on  a  large  scale  this  process,  however,  is 
but  seldom  employed,  because  tempering  in  a  muffle  heated 
to  a  dark-brown  heat  is  cheaper  and  the  result  more  uni- 
form and  assured. 


LIQUIDS    USED    IN    QUENCHING    STEEL. 


Ill 


Small  tools  which  are  to  possess  the  hardness  of  a  spring 
may  be  tempered  in  an  oil  which  may  be  heated  to  554° 
F.  before  it  inflames.  For  this  operation  the  oil  is  heated 
in  an  iron  vessel  containing  the  articles  to  be  tempered 
until  it  commences  to  bubble.  The  vessel  is  then  quickly 
covered  with  a  close-fitting  lid,  removed  from  the  fire  and 
allowed  slowly  to  cool. 

This  mode  of  tempering  is  very  suitable  in  manufacturing 
on  a  large  scale  if  devices  are  provided  by  means  of  which 

FIG.  57. 


the  rise  in  the  temperature  of  the  oil  can  be  closely  watched 
so  that  the  oil  is  heated  to  near  the  inflaming  point,  but 
never  up  to  it,  or  even  above  it. 

The  device  shown  in  Fig.  57,  which  is  of  French  origin, 
answers  the  above-mentioned  requirements. 

An  iron  kettle  A  is  heated  by  a  gas  flame  (illuminating 


112  TOOL-STEEL. 

gas)  so  arranged  that  it  can  be  readily  turned  off.  A  small 
perforated  vessel  a  which  fits  in  the  kettle  and  reaches 
nearly  to  the  bottom  of  the  latter  serves  for  the  reception  of 
the  tools  to  be  tempered.  The  bipartite  lid  d  is  secured  by 
means  of  screw  clamps.  From  one  part  of  the  cover,  a 
pipe  R  leads  to  a  vessel  filled  with  water  which  serves  for 
condensing  the  oil  vapors  or  for  carrying  off  oil  boiling 
over.  This  part  of  the  lid  also  contains  the  pyrometer  P. 

The  oil  is  heated  to  about  500°  F.  and  allowed  to  remain 
at  this  temperature  for  an  accurately  measured  length  of 
time.  The  gas  flame  is  then  turned  off  and  the  kettle 
allowed  slowly  to  cool,  or  the  tools  are  taken  from  the  oil 
and  a  fresh  supply  of  tools  is  introduced. 

In  reference  to  the  devices  for  tempering  it  may  be 
added  that  they  must  be  adapted  as  much  as  possible  to  the 
demand  for  uniform  heating  of  the  tools.  Even  with  tools 
only  partially  to  be  tempered,  the  heat  must  evenly  extend 
over  the  portion  to  be  tempered. 

Tempering  may  be  effected  in  an  open  fire ;  a  bright 
glow  or  sooting  flame  must  however  be  avoided,  and 
eventually  a  piece  of  sheet  iron  is  placed  between  the  tool 
to  be  tempered  and  the  fire. 

For  tempering  smaller  tools  red  hot  iron  is  mostly  used, 
it  being  brought  into  close  contact  with  the  surface  to  be 
tempered. 

Perforated  tools  are  tempered  by  pushing  a  red  hot 
mandril  into  the  bore. 

Disc-like  tools  are  placed  between  red  hot  iron  plates  of 
smaller  circumference  than  the  tools. 

Tempering  is  frequently  effected  by  means  of  a  gas  flame 
which,  however,  should  not  be  pointed. 


LIQUIDS    USED    IN    QUENCHING    STEEL. 


113 


Tempering  by  means  of  hot  sand  may  be  effected  with 
the  use  of  an  open  fire  by  heating  the  sand  upon  sheet-iron 
and  then  tempering  the  tools  in  it.  For  tempering  larger 


tools,  or  a  number  of  them  a  special  furnace,  as  shown  in 
Fig.  58,  may  be  used. 

A  perforated  iron  plate  kept  constantly  red  hot  may  be 
used  in  a  similar  manner.     The  tempering  furnace  may 
then  be  constructed  like  an  ordinary  kitchen  hearth. 
8 


114 


TOOL-STEEL. 


Partial  tempering  of  tools  in  molten  lead  may  be  recom- 
mended for  the  purpose  of  producing  a  degree  of  hardness 
running  very  evenly  from  one  end  to  the  other. 

The  portion  of  the  tool  which  is  to  be  entirely  tempered 
is  immersed  in  the  molten  lead,  which  causes  it  to  be 
heated  very  slowly  and  evenly.  The  temper  colors  progress 
uniformly  on  the  portions  of  the  tool  outside  of  the  lead. 

Tempering  of  large  tools  which  have  to  be  evenly  heated 
in  the  direction  of  their  length  requires  special  devices  to 
obtain  a  uniform  tempering  temperature.  A  furnace  which 
serves  for  tempering  long  knives  is  shown  in  Fig.  59. 

FIG.  59. 


A  sheet-iron  box  Tof  trapezoid  cross-section  rests  upon 
iron  legs  F.  In  place  of  a  bottom  it  is  furnished  with  iron 
rods  R  forming  a  grate.  The  interior  of  the  box  is  lined 
with  thin  fire  brick  or  with  fire  clay.  The  knives  M  to  be 
tempered  rest  upon  a  few  cross  rods  o  over  the  upper  por- 
tion of  the  box.  The  whole  is  closed  with  a  sheet-iron 
cover  B  which  is  provided  in  the  centre,  in  the  direction  of 
its  length,  with  an  opening  for  the  escape  of  the  gases. 

For  use,  glowing  charcoal  is  evenly  distributed  over  the 
grate  R  and  upon  this  is  placed  fresh  charcoal  the  size  of  a 
nut.  When  all  the  charcoal  is  in  full  glow,  the  knives  are 
placed  in  position  as  shown  in  the  illustration  and  tem- 
pered. 


LIQUIDS    USED    IN    QUENCHING    STEEL. 


115 


The  small  furnace,  above  described,  should  be  placed  in 
a  room  in  such  a  manner  as  to  prevent  the  possibility  of 
the  charcoal  burning  unevenly  by  reason  of  draughts.  If 
the  charcoal  burns  less  bright  in  some  places  than  in  others, 
it  may  be  remedied  by  blowing  with  a  hand  bellows  or  by 
pushing  pieces  of  sheet-iron  below  the  grate  at  the  places 
where  the  fire  is  too  bright. 

Fig.  60  shows  the  same  furnace  constructed  of  brick. 

FIG.  60. 


In  order  to  be  sure  of  the  production  of  a  uniform  heat 
an  air  chamber  may  be  fixed  beneath  the  grate,  the  air  be- 
ing introduced  by  means  of  a  perforated  gas  pipe  (see  Fig. 
59).  This  may  in  a  similar  manner  be  done  with  the  brick 
furnace,  Fig.  60. 

The  temper  of  the  steel  is  fixed  by  either  quenching 
rapidly  from  the  temperature  attained  or  by  allowing 
slowly  to  cool. 

The  tempered  tool  may  be  allowed  slowly  to  cool  if  it  did 
not  contain  more  heat  than  was  required  for  tempering. 

If  the  tool  had  been  partially  heated,  more  than  neces- 
sary for  tempering,  it  must  be  rapidly  cooled  to  prevent 
softening. 

Cooling  may  be  effected  by  plunging  the  tool  in  rapid 
succession  in  water  or  allowing  it  slowly  to  cool  in  mild 


116  TOOL-STEEL. 

oils  or  fats.  If  hardening  of  portions  of  the  tool  which  are 
still  at  the  hardening  temperature  is  to  be  avoided,  the  tool 
for  the  purpose  of  fixing  the  temper  is  plunged  in  soap 
water. 

In  tempering  partially  hardened  tools  an  error  is  fre- 
quently committed  in  heating  them  too  far  back  of  the 
edges,  and  for  the  purpose  of  cooling  placing  the  tools — 
which  in  themselves  are  properly  hardened  and  tempered — 
with  the  edges  foremost  in  shallow  water.  The  heat  pene- 
trating from  the  too  highly  heated  portions  towards  the 
hardened  parts  standing  in  the  water  causes  a  sharp  boun- 
dary to  be  formed  between  the  hardened  and  unhardened 
parts,  and  along  this  boundary  the  edges  are  sure  to  break 
off.  This  error  ma}r  be  avoided  by  nrst  plunging  the  tools 
in  soap  water  to  withdraw  from  them  the  highest  heat. 
The  above  mentioned  error  is  frequently  made  in  hardening 
hand  chisels,  hot  and  cold  chisels,  drills,  rock  drilling 
tools,  etc. 


XIV. 

STRAIGHTENING  TOOLS. 

TOOLS  which  have  become  distorted  in  hardening  cannot 
be  straightened  while  in  a  cold  state  without  danger  of 
breaking  them.  Hence  this  operation  is,  as  far  as  possible, 
combined  with  that  of  tempering,  because  the  steel  while 
still  in  a  heated  state  possesses  sufficient  plasticity  to  allow 
of  being  straightened. 


STRAIGHTENING    TOOLS.  117 

Straightening  the  steel  may  be  effected  : 

1.  By  pressure. 

2.  By  bending  and  twisting  by  means  of  straightening 
claws. 

3.  By  blows  with  the  straightening  and  chasing  ham- 
mer. 

4.  By  uneven  heating  and  cooling  during  tempering. 
The  distortion   of  tools   during    hardening  is,   in   most 

cases,  caused  by  uneven  heating  or  uneven  cooling,  and 
tools  of  a  slight  cross-section  and  greater  length  or  width 
are  more  frequently  affected  than  tools  of  a  larger  cross- 
section.  Uneven  cooling  causes  uneven  changes  in  volume, 
and  consequently  the  steel  becomes  distorted. 

Tools  which  have  undergone  hardening  by  pressure  are 
straightened  during  the  operation  of  hardening,  i.  e.,  their 
becoming  distorted  is  prevented  during  cooling. 

Thin,  flat  tools  which  cannot  be  readily  straightened 
with  the  hammer  are  firmly  clamped,  whilst  in  the  temper- 
ing temperature,  between  two  hand-warm  iron  plates  and 
allowed  to  cool. 

Long  tools  of  symmetrical  cross-section — for  instance, 
twist  augers,  broaches,  etc. — are  straightened  under  a  hand- 
warm  screw-press. 

Flat  tools  which  become  easily  distorted  in  hardening 
are  straightened  by  means  of  straightening-claws  imme- 
diately after  tempering  or  during  that  operation. 

For  the  purpose  of  straightening,  one  end  of  the  tool  is 
clamped  in  a  vice  while  the  other  end  is  grasped  with  the 
straightening-claw,  and  the  tool  is  slowly  twisted  straight. 
In  simple  cases  two  straightening-claws  may  be  used. 
Such  straightening-claws  are  easily  made  by  bending  one 


118  TOOL-STEEL. 

end  of  an  iron  bar,  as  shown  in  Fig.  61.     For  the  purpose 
of  straightening  the  tool  is  laid  in  the  clefts  S. 

Tools  distorted  to  an  undulatory 
or  crescent-shaped  form  can  be 
straightened  only  with  difficulty 
by  pressure,  and  not  at  all  by 
means  of  straightening  claws. 
Straightening  must  then  be  ef- 
fected by  blows,  which  requires 
much  skill  and  experience. 

The  tools  required  for  this  purpose  are  as  follows : 

A  straightening  anvil,  i.  e.,  an  anvil  with  a  large  some- 
what convex  face  which  should  be  smooth  and  thor- 
oughly hardened. 

A  straightening  hammer,  i.  e.,  a  copper  hammer  with 
two  broad  faces  of  different  convexity,  and  a  steel 
straightening  hammer  with  a  broad  convex  face  and 
a  narrow  sharply  rounded  face  which  stands  in  the 
direction  of  the  hammer-helve. 

The  blows  with  the  hammer  should  always  be  given  on 
the  hollow  side  of  the  tool.  Jf  vigorous  blows  with  the 
flat  side  of  the  hammer  do  not  suffice,  the  sharp  face  has  to 
be  applied,  the  latter  producing  a  powerful  drawing-out 
effect  in  the  vertical  direction  towards  the  edge.  Blows 
incorrectly  applied  readily  cause  worse  distortion  of  the 
tool.  The  short  time  the  latter  remains  in  the  suitable 
temperature  requires  quick  and  sure  work. 

Straightening  of  tools  by  uneven  heating  and  cooling  in 
tempering  or  wrhen  the  tool  is  cold,  can  only  be  done  in 
rare  cases  and  when  the  tool  is  but  slightly  distorted. 
Such  tools  are  laid,  hollow  side  down,  upon  the  temper- 


CASE-HARDENING.  119 

ing  furnace  or  on  a  hot  iron  plate,  and  cooled  upon  the  con- 
vex side  until  they  have  become  straight. 


XV.  -•      - 

CASE-HARDENING    AND    PREVENTAT1VES 

AGAINST   SUPERFICIAL   DECARBON- 

IZATION  AND  OVERHEATING. 

THE  process  of  case-hardening  or  surface-hardening  is 
made  use  of  if  steel  with  but  little  capacity  for  hardening, 
or  iron  not  capable  of  being  hardened,  is  to  be  supplied  with 
a  hard  surface,  the  object  being  attained  by  cementation. 

If  iron  is  for  some  time  heated  in  intimate  contact  with 
substances  rich  in  carbon  and  which  readily  yield  it,  it  ab- 
sorbs carbon,  the  latter  penetrating  the  further  from  the 
surface  towards  the  centre  the  higher  the  temperature  is, 
and  the  longer  heating  has  been  continued.  The  carbon 
absorbed  during  heating  imparts  to  the  iron  the  capacity  of 
being  hardened,  or  increases  that  of  steel  capable  of  being 
but  slightly  hardened. 

When  heating  with  carbon  is  effected  at  a  high  tempera- 
ture and  for  a  longer  time,  the  structure  of  the  steel  or  iron 
undergoes  a  change,  it  becoming  coarsely  crystalline,  and 
the  cohesion  between  its  particles  is  loosened.  The  conse- 
quence of  this  is  a  brittle  shortness  which  is  increased  in 
the  hardened  state  if  the  fine  structure  is  not  previously  re- 
stored by  forging.  Hence  to  avoid  failure  as  regards  the 
quality  of  the  product,  the  temperature  should  not  be  too 
high  nor  heating  continued  too  long. 


120  TOOL-STEEL. 

By  case-hardening  a  layer  of  the  tool  extending  to  a 
greater  depth  is  rendered  harder.  A  tool  of  a  smaller  cross- 
section  may  even  have  absorbed  carbon  throughout  and 
have  become  capable  of  being  hardened. 

It  is  not  always  desirable  to  impart  to  tools  a  hardness 
penetrating  to  a  greater  depth,  a  very  superficial  higher 
degree  of  hardness  being  frequently  only  required,  and  this 
is  obtained  by  so-called  "  burning  in." 

The  method  pursued  in  the  operation  of  case-hardening 
is  as  follows  : 

The  tools  are  packed  in  an  iron  box  with  charcoal 
powder  so  as  to  be  uniformly  covered  on  all  sides.  The 
box  is  then  covered  with  a  tightly  fitting  lid,  and  after  all 
the  joints  have  been  made  air-tight  by  daubing  with  clay, 
it  is  placed  in  the  muffle  of  a  muffle  furnace,  or  in  an 
annealing  furnace  (see  Fig.  20).  Heating  to  a  uniform 
temperature  is  effected  in  the  same  manner  as  in  annealing, 
and  the  box  is  kept  at  this  temperature  for  a  longer  or 
shorter  time,  according  to  the  degree  of  hardness  desired. 
The  heat  should  not  exceed  a  bright  cherry -red,  otherwise 
the  tools  may  readily  be  ruined.  As  a  rule  the  tools  are 
at  once  hardened  at  this  temperature  and  are  but  seldom 
allowed  to  cool  and  then  reheated  for  hardening. 

In  practice  case-hardening  is  resorted  to  in  the  manu- 
facture on  a  large  scale  of  tools  or  machine-parts  which  for 
the  sake  of  cheapness  are  made  of  wrought  iron  or  have 
been  cast,  for  instance,  for  sewing  machines,  parts  of 
-bicycles,  tools  forming  constituent  parts  of  household 
utensils,  and  even  scissors,  knives,  hatchets,  etc.  The 
carbonaceous  substances  employed  are  used  either  in  a  pure 
state  or  mixed  according  to  their  efficiency  as  found  by  ex- 


CASE-HARDENING. 


121 


perience.  When  charcoal  is  used,  preference  should  be 
given  to  that  of  linden  or  bass-wood  ;  soot  is  less  frequently 
employed  and  has  no  advantage  over  charcoal.  Charcoal 
obtained  by  charring  animal  substances,  such  as  leather, 
horn  and  bone,  is  very  much  liked  for  case-hardening, 
charred  leather  being  preferred  above  all,  since  experience 
has  proved  it  to  be  most  efficacious. 

Animal  substances  dried  and  ground  to  powder,  or  cut 
up  in  shavings,  for  instance,  horn  and  hoof  powdered  or  in 
shavings,  glue,  etc.,  are  milder  in  their  action,  do  not 
cement  so  rapidly  as  charcoal,  and  require  longer  time  for 
heating.  Hence  they  are  but  seldom  used  for  case-harden- 
ing, but  frequently  as  a  protection  of  the  surfaces  of  larger 
tools,  to  avoid  superficial  decarbonization  or  to  withdraw 
them  from  the  direct  action  of  the  fuel. 

Tools  to  acquire  an  even  degree  of  hardness  by  case- 
hardening  must  be  free  from  adhering  foreign  substances, 

FIG.  62. 


i.  e.,  must  have  a  pure  metallic  surface,  and  hence  have  to 
be  scoured  before  being  placed  in  the  box. 

If  certain  portions  of  the  surfaces  of  the  tools  are  to  re- 
main soft,  they  are  protected  from  cementation  by  coating 
them  with  a  clay  paste  or  packing  them  in  substances 
which  yield  no  carbon  (sand,  brick-dust,  etc.). 

Fig.  62  illustrates  the  manner  of  packing  a  spindle  which 
is  to  be  hard  in  two  places.  The  spindle  packed  as  shown 


122  TOOL-STEEL. 

in  the  illustration  is  for  several  hours  exposed  to  a  bright 
red  heat,  then  taken  from  the  packing  and  hardened. 

"  Burning  in  "  requires  the  use  of  substances  which  yield 
their  carbon  with  ease  and  rapidity  when  in  contact  with 
the  tools  at  a  higher  temperature.  According  to  experience 
yellow  prussiate  of  potash  is  the  most  effective  agent. 
When  brought  in  contact  with  the  red-hot  tool  it  liquefies, 
and  in  this  condition  exerts  a  powerful  cementing  effect. 
The  mode  of  operation  is  as  follows : 

Heat  the  tool  to  a  red  heat  and  scatter  yellow  prussiate 
of  potash  over  the  surface  to  be  burnt  in,  it  being  best  to 
use  a  fine-meshed  sieve  for  the  purpose,  so  as  to  be  sure  of 
the  even  distribution  of  the  salt.  The  tool  is  then  returned 
to  the  fire,  heated  to  the  hardening  temperature  and  hard- 
ened. For  a  greater  depth  of  hardness  on  iron  or  very  soft 
steel  repeat  the  operation  twice  or  three  times.  The  surface 
of  the  tool  must  of  course  be  free  from  scale.  Very  small 
tools  which  are  to  be  given  a  high  degree  of  hardness  are 
treated  as  follows : 

Melt  yellow  prussiate  of  potash  in  an  iron  vessel  over  a 
moderate  fire  and  bring  the  tool  previously  heated  to  a 
brown-red  heat  into  the  fused  salt,  and  allow  it  to  remain 
in  it  up  to  15  minutes.  The  tool  is  then  heated  to  the 
hardening  temperature  and  hardened. 

With  small,  thin  tools,  a  similar,  though  somewhat 
milder,  effect  is  obtained  by  repeatedly  bringing  them  to  a 
red  heat,  slowly  plunging  them  in  oil  or  fat,  reheating 
them  each  time,  and  finally  hardening  in  water.  If  the 
effect  is  to  be  heightened,  mix  with  the  oil  or  fat  (train  oil) 
sufficient  soot  or  charcoal  powder  to  make  a  pasty  mass  and 
plunge  the  red  hot  tool  in  the  mixture.  The  tool  becomes 


CASE-HARDENINGL  123 

coated  with  a  thick  layer  of  the  paste,  which  burns  with 
difficulty  and  by  subsequent  heating  effects  powerful 
cementation. 

By  mixing  flour,  yellow  prussiate  of  potash,  saltpetre, 
horn  shavings  or  hoof  meal,  fat  and  wax,  a  mass  of  paste- 
like  consistence  is  obtained,  which  may  serve  for  the  same 
purpose.  The  different  mixtures  brought  into  commerce 
under  the  name  of  "  hardening  paste  "  are  of  similar  com- 
position, and  the  ingredients  may  be  chosen  at  will.  For 
instance,  melt : 

Wax 500  parts  by  weight. 

Tallow 500 

Kosin 100         "  " 

Add  to  the  melted  mass  a  sufficient  quantity  of  equal 
parts  of  charred  leather,  horn  shavings  and  hoof  meal  to 
make  it  of  a  paste-like  consistence,  then  add  10  parts  by 
weight  of  saltpetre,  and  50  to  100  parts  by  weight  of 
powdered  yellow  prussiate  of  potash,  and  stir  thoroughly. 

The  tools  to  be  burnt  in  are  plunged,  while  in  a  red  hot 
state,  in  the  paste,  allowed  to  cool  in  it,  again  heated  and 
hardened. 

A  hardening  powder  to  be  scattered  upon  tools  which 
are  to  be  hardened  after  heating  in  the  open  fire,  may  be 
made  of  any  desired  mixture  of  yellow  prussiate  of  potash, 
charcoal,  rosin,  calcined  common  salt,  saltpetre,  hoof  meal, 
glass  powder,  etc.  It  must,  however,  be  borne  in  mind 
that  the  only  purpose  of  the  substances  which  do  not  yield 
carbon,  is  to  effect  a  better  adhesion  and  uniform  distribu- 
tion of  the  mixture  as  well  as  to  destroy  oxides  (scale),  and 
therefore  the  carbonaceous  constituents  must  preponderate. 


^UNIVERSITY 


124  •      TOOL-STEEL. 

The  examples  given  below  may  serve  as  illustrations  of  the 
composition  of  a  dry  hardening  powder  : 

Hoof  meal 10  parts. 

Charred  horn 10     '• 

Saltpetre £     " 

Glass  powder £     " 

Calcined  common  salt 2     fc ' 

Yellow  prussi ate  of  potash 1     k' 

In  the  manufacture  of  tools  the  agents  for  the  production 
of  a  higher  degree  of  hardness  on  the  surface  are  of  second- 
ary importance,  it  being  generally  preferred  to  use  steel  of 
such  hardness  as  will  allow  of  the  degrees  of  efficiency 
required  and  which  can  be  hardened  without  the  assistance 
of  hardening  agents. 

Of  greater  importance,  however,  are  agents  for  cooling 
tools  which  have  been  heated  partially  too  rapidly  or  to 
too  high  a  degree ;  further,  as  a  protection  against  contact 
with  the  combustion-gases  or  against  partial  decarboniza- 
tion  in  heating. 

Tools  with  sharply  projecting  portions  on  their  surfaces, 
for  instance,  cutters,  files,  etc.,  can  only  with  difficulty  be 
heated  to  an  even  temperature  without  the  corners  and 
edges  (teeth)  becoming  heated  earlier,  and  finally  to  a 
higher  degree,  than  the  thicker  body.  The  consequence  of 
this  is  that  the  edges  acquire  too  brittle  a  hardness,  further, 
cracks  are  formed,  and  with  long  continued  over-heating, 
decarbonization  takes  place  and  the  tools  remain  soft  after 
hardening. 

In  many  cases,  for  instance,  in  hardening  files,  it  be- 
comes necessary  to  protect  the  teeth  from  overheating  and 
decarbonization,  and  with  other  tools,  for  instance,  cutters, 


CASE-HARDENING.  125 

to  cool  them  during  heating  when  they  have  become  hot 
too  soon. 

Cooling  of  unevenly  heated  tools  is  effected  by  taking 
them  from  the  fire  and  allowing  them  to  cool  in  the  air  to  a 
uniform  temperature  after  which  they  are  re-heated.  The 
result  of  this  process  is,  however,  not  always  satisfactory, 
especially  when  there  are  considerable  differences  in  the 
cross  sections  of  the  tool.  In  such  case  the  use  of  a  powder 
which  effects  cooling  and  prevents  possible  decarbonization 
may  be  decidedly  recommended,  and  such  powder  should 
always  be  on  hand  when  hardening  complicated  tools.  A 
suitable  powder  is  obtained  by  mixing  the  following  in- 
gredients : 

Hoof  meal 50  parts. 

Rye  flour. 5     " 

Common  salt,  calcined  and  powdered 25     " 

Glass  powder , \     " 

Or, 

Common  salt,  calcined 1  part. 

Hoof  meal 1     " 

Charred  leather,  pulverized 1     u 

Eye  flour 1     " 

For  use  scatter  the  powder  by  means  of  a  small  shovel 
upon  the  portions  of  the  tool  which  at  the  outset  show  a 
higher  heat,  or  dip  them  in  the  powder,  repeating  the 
operation  as  often  as  necessary.  The  application  of  the 
powder  is  of  use  only  with  complicated  tools. 

If  the  surfaces  are  at  the  outset  to  be  protected,  the  tools, 
for  the  purpose  of  heating,  are  packed  in  a  box  between 
horn  shavings  and  hoof  meal,  and  heated  together  with  the 
box  ;  or  the  tools,  previous  to  hardening,  are  coated  with 
a  firmly  adhering  paste  of  carbonaceous  substances.  This 


126  TOOL-STEEL. 

coat  is  allowed  to  dry  and  the  tools  are  then  heated  as 
usually  for  hardening. 

For  this  purpose,  the  mixtures  given  below,  which  are  to 
be  applied  in  a  pasty  condition,  may  be  used  : 

Charcoal  or  charred  leather 1  part. 

Common  salt 1     " 

Eye  flour 1     " 

Or, 

Hoof  rneal 4  parts. 

Eye  flour 1  part. 

Yellow  prussiate  of  potash  1  per  cent,  by  volume. 

Glass  powder 1         "  " 

Or, 

Hoof  meal 2  parts. 

Charred  leather 2     " 

Calcined  horn  meal 2      " 

Potassium  chromate 1  part. 

Yellow  prussiate  of  potash 1     " 

Eye  flour 2  parts. 

The  ingredients,  previously  reduced  to  a  fine  powder  and 
intimately  mixed,  are  made  into  a  paste  with  concentrated 
common  salt  solution.  The  mixture  is  allowed  to  stand 
quietly  for  a  few  days,  then  thoroughly  stirred,  and  for  use 
applied  with  a  brush  to  the  tools,  which  should  be  pre- 
viously freed  from  adhering  grease.  To  prevent  the  mass 
from  peeling  off  when  heated,  it  should  be  thoroughly  dry 
before  hardening  the  tools  coated  with  it. 

The  composition  of  the  mixtures  given  above  may, 
of  course,  be  varied  in  any  manner  as.  desired  and  suited 
for  the  purpose  in  view.  Only  in  rare  cases  is  their  use 
connected  with  any  disadvantages,  the  principal  of  them 
being  that  the  hardened  tool  shows  a  spotted  appearance, 
due  to  the  mass  having  in  some  places  been  burnt  to  it. 


WELDING    OF    STEEL.  127 

For  case-hardening  steel  by  cementation,  carbon  com- 
pounds in  gaseous  form  are  also  used.  If,  for  instance, 
illuminating  gas  is  conducted  over  the  surface  of  red-hot 
steel,  it  exerts  a  cementing  effect  of  great  energy,  the  sur- 
face of  the  steel  becoming  hard  when  rapidly  cooled. 

This  process  is  practically  applied  to  armor-plates  to 
which  a  hard  surface  is  to  be  given.  For  this  purpose  car- 
buretted  hydrogen,  formed  by  the  immersion  of  calcium 
carbide  in  water,  is  used.  The  gas  is  conducted  over  the 
surface  of  the  red-hot  armor-plate,  the  air  being  excluded. 

Pig  iron  is  seldom  employed  for  surface-hardening.  It 
contains  a  high  percentage  of  carbon,  which  it  readily 
yields  to  iron  or  steel  when  it  is  brought  into  intimate  con- 
tact with  it,  or  when  it  is  made  to  fuse  on  the  surface 
of  red-hot  iron.  The  practical  value  of  this  mode  of  sur- 
face-hardening is  very  small,  and  the  same  result  can,  with 
greater  certainty,  be  attained  by  case-hardening,  or  burn- 
ing in. 


XVI. 

WELDING  OF  STEEL. 

THE  operations  in  welding  steel  involve  the  overheating 
of  the  latter  to  a  high  degree,  and  consequently  it  may 
readily  be  burnt.  It  should  be  borne  in  mind  that  for 
welding,  steel  has  to  be  heated  to  a  less  degree  than  iron, 
and  only  high  enough  to  produce  a  pasty  condition  of  the 
surface ;  iron,  on  the  other  hand,  may  be  softened  to  a 
greater  depth.  When  steel  is  heated  to  a  greater  depth  to 


128  TOOL-STEEL. 

a  scintillating  white  heat,  its  structure  loses  its  coherence 
to  such  an  extent  that  in  the  subsequent  forging  the  steel 
will  crumble. 

The  formation  of  a  soft  layer  on  the  surface  of  the  steel  is 
an  absolute  necessity  for  welding.  This  state  ot  softness  is 
obtained  by  bringing  the  steel  to  a  bright  yellow  heat,  the 
operation  being  assisted  by  scattering  upon  the  steel  agents 
readily  fusible  by  themselves,  and  which  protect  the  work 
from  oxidation.  Such  agents  are  :  Borax,  fine  quartz  sand, 
clay,  dried  and  pulverized  or  brick-dust,  potash,  soda,  sal 
ammoniac,  etc.,  which  may  be  used  in  a  mixture  of  any 
desired  proportions.  Borax  and  soda  are  fused  before  use- 
and  pulverized  after  cooling. 

The  operation  of  welding  is  carried  on  as  follows :  The 
parts  to  be  welded  are  carefully  scarfed  and  fitted  together. 
They  are  then  brought  to  the  welding  heat,  which  for  soft 
steel  should  be  dark  white,  for  hard  steel  bright  yellow, 
and  for  iron  scintillating  white.  The  scale  formed  in  heat- 
ing is  scraped  off,  and  shortly  before  attaining  the  welding 
heat,  the  welding  powder  is  applied  without,  however,  tak- 
ing the  work  from  the  fire.  The  work  is  then  quickly 
taken  from  the  fire ;  the  parts  to  be  welded  are  pressed 
together,  a  superficial  union  is  effected  by  light  hammer 
blows,  or  still  better  by  pressure.  Welding  powder  is 
again  scattered  upon  the  weld,  the  work  returned  to  the 
fire  and  again  brought  to  the  welding  heat,  which,  how- 
ever, need  not  be  so  high  as  the  first. 

Union  is  now  effected  by  more  vigorous  hammer  blows, 
and  the  finer  structure  of  the  steel  is  restored  by  forging 
continued  as  long  as  possible.  To  avoid  the  formation  of 
cracks,  the  tool  must  next  be  allowed  slowly  to  cool,  and  is 
then  reheated  for  subsequent  hardening. 


REGENERATION    OF    STEEL.  129 

If  the  weld  does  not  turn  out  satisfactorily,  the  respective 
pieces  have  to  be  removed  before  repeating  the  operation. 

If,  after  welding,  the  steel  shows  edge  cracks,  it  has  been 
overheated  and  burnt ;  or  it  is  unsuitable  for  welding  ifr 
after  carefully  repeating  the  operation,  such  cracks  are 
still  perceptible  and  the  weld  does  not  turn  out  satisfactorily. 


XVII. 

REGENERATION    OF    STEEL   WHICH    HAS   BEEN 
SPOILED  IN  THE  FIRE. 

WHEN  steel  has  been  overheated  to  a  high  degree  or 
roasted,  it  is  best  not  to  work  it  further  for  tools  and  spend 
money  in  their  manufacture,  since  they  will  be  brittle  and 
crack,  or  do  not  acquire  hardness. 

As  a  rule  it  is  found  out  too  late  that  the  steel  has  been 
overheated  or  roasted,  it  being  recognized  only  by  the  de- 
fects of  the  finished  tool.  Regeneration,  i.  e.,  an  improve- 
ment of  the  spoiled  steel,  is  then  out  of  the  question.  In 
the  manufacture  of  tools,  nostrums  for  improving  spoiled 
steel  are  of  no  appreciable  value,  the  best  means  being  to 
avoid  mistakes. 

Steel  is  burnt  when  it  has  been  heated  to  such  a  degree  as 
to  cause  its  structure  to  be  dissevered,  in  consequence  of 
which  the  steel  in  a  hardened  state  shows  edge  cracks.  In 
forging  such  steel  it  crumbles  :  in  hardening  it  cracks.  It 
cannot  be  regenerated. 

Steel  is  overheated  when  it  has  been  brought  to  above  a 
bright-red  heat,  and  in  consequence  of  it  acquires  a  coarse 
9 


130  TOOL-STEEL. 

•crystalline  structure,  which,  according  to  the  duration  of 
overheating,  is  confined  to  the  surface — edges  and  corners 
— or  extends  throughout  the  bulk  of  the  steel. 

If  in  forging  tool-steel  has  been  partially  overheated,  and 
it  is  considered  advisable  not  to  remove  the  respective  por- 
tion entirely,  it  is  allowed  to  cool  to  a  cherry-red  heat,  and 
then  subjected  to  vigorous  working,  which  is  continued  to  a 
dark-red  heat.  The  tool  having  been  allowed  slowly  to 
<3Ool  is  then  carefully  reheated  for  subsequent  hardening. 

Tools  which  have  been  overheated  in  hardening  are 
.allowed  slowly  to  become  cold,  and  are  then  carefully  re- 
heated to  the  lowest  hardening  temperature  permissible. 
By  this  process  the  fine  structure  is  restored  and  the  steel 
regenerated.  All  nostrums  recommended  for  the  regenera- 
tion of  burnt  or  overheated  steel  have  the  same  object  in 
view,  and  by  themselves  are  entirely  without  effect.  Suc- 
cess in  attempting  to  regenerate  overheated  steel  is  always 
doubtful. 

Tool  steel  is  roasted  or  baked  if,  with  the  access  of  air,  it 
has  for  some  time  been  exposed  to  a  temperature  which  by 
itself  is  not  high  enough  to  cause  overheating. 

From  the  surface  of  such  steel  the  content  of  carbon  has 
been  partially  or  entirely  withdrawn.  Tools  manufactured 
from  it  do  not  acquire  a  sufficient  degree  of  hardness, 
or  remain  entirely  soft.  If  a  tool  is  suspected  of  having 
been  made  of  slightly  roasted  steel  one  of  the  previously 
described  hardening  agents,  best  in  the  form  of  a  paste, 
may  be  used ;  success  depends  on  the  degree  of  decarboni- 
zation,  and  is  always  doubtful. 

Steel  is  called  dead  when,  while  in  use,  it  has  been  re- 
peatedly heated  and  hardened,  and  in  consequence  has 


DEFECTS    OF    HARDENED    TOOLS.  131 

become  brittle,  has  lost  cutting  power,  and  cracks  readily  in 
hardening.  There  are  no  other  means  of  overcoming  this 
than  by  removing  the  worn-out  edge  of  the  tool  and  re- 
newing it. 


XVIII. 

INVESTIGATION  OF  DEFECTS  OF  HARDENED 

TOOLS. 

IF  in  inspecting  hardened  tools  defects  are  found  their 
causes  should  be  immediately  determined,  so  as  to  avoid 
them  in  subsequent  operations.  The  art  of  hardening  is  a 
very  difficult  one,  and  requires  great  skill  and  long  experi- 
ence if  to  be  carried  on  with  success.  Such  experience 
does  not  alone  include  a  superficial  knowledge  of  the  hard- 
ening process  to  be  employed  in  each  case,  but  also  an 
accurate  perception  of  the  causes  of  defects  and  the  selection 
of  the  methods  of  working  by  which  they  may  be  avoided. 
The  hardener  of  tools  should  from  the  start  have  a  clear 
idea  as  to  the  process  by  which  the  object  in  view  can  be 
attained  without  probable  failure,  and  should  take  measures 
that  the  various  operations  in  hardening  can  be  carried  on 
without  hindrance. 

When  many  tools  of  the  same  kind  are  to  be  hardened, 
the  operation  should  commence  with  one  piece,  which  im- 
mediately after  hardening  is  cleaned  under  water  by  means 
of  a  sharp  brush,  and  then  examined  as  to  cracks,  and  by 
means  of  a  smooth  file  as  to  the  degree  of  hardness.  If  no 
defect  is  discovered,  a  second  piece  may  be  taken  in  hand, 


132  TOOL-STEEL. 

the  examination  of  which  will  show  whether  the  hardening 
process  adopted  is  a  suitable  one,  and  whether  the  opera- 
tion may  be  continued  in  rapid  succession.  Nevertheless  it 
must  not  be  omitted  to  subject  the  tools  immediately  after 
hardening  to  a  cursory  examination,  and  subject  individual 
pieces  to  a  searching  inspection. 

With  the  use  of  too  high  a  temperature,  small  tools 
hardened  all  over  crack  already  during  cooling  ;  this  defect 
can  at  once  be  dealt  with. 

The  severance  of  corners  and  edges  of  larger  tools  also 
occurs  mostly  in  the  hardening  bath,  but  at  a  later  stage  of 
cooling,  so  that  the  tools  have  to  be  allowed  to  rest  for 
some  time  before  the  hardener  can  be  assured  that  the 
work  proceeds  correctly  and  that  hardening  may  be  con- 
tinued ;  otherwise  it  may  happen  that  in  the  subsequent 
inspection  all  the  hardened  pieces  may  be  found  defective. 

Although  too  great  an  assurance  in  the  correct  selection 
of  the  hardening  process,  without  scrupulous  inspection 
frequently  repeated,  may  lead  to  failure,  uncertainty  and 
timidity  are  just  as  objectionable.  Precaution  is  then  car- 
ried so  far  that  larger  tools  are  for  hours  roasted  in  the 
open  fire  to  bring  them  to  a  quite  uniform  heat,  and  never- 
theless are  finally  hardened  in  an  insufficient  temperature. 
It  may  happen  that  this  process  is  several  times  repeated, 
because  in  this  way  the  tool  does  not  acquire  hardness,  and 
the  steel  used  is  then  blamed.  Such  uncertainty  is  charac- 
teristic of  an  inexperienced  hardener. 

The  following  hints  may  serve  as  guides  in  the  in- 
spection : 

1.  Small  tools,  or  tools  of  a  small  cross-section,  which 
have  been  partially  hardened,  show  cracks  in  the 


DEFECTS    OF    HARDENED    TOOLS.  133 

centre  running  in  the  direction  of  the  length  in  case 
they  have  been  too  highly  heated,  or  if  cracking  has 
been  due  to  flaws  contained  in  the  steel  before  hard- 
ening. Break  the  thoroughly  dried  tool  and  com- 
pare the  structure  of  the  fractures  with  a  sample 
of  steel  of  the  same  cross-section  and  of  the  same 
quality,  which  has  been  carefully  brought  to  a 
cherry-red  heat,  hardened,  and  then  broken. 

If  the  fracture  of  the  tool  shows  a  coarser  struc- 
ture than  the  sample,  hardening  has  been  effected  at 
too  high  a  temperature.  If  the  structure  is  fine  and 
the  sides  of  the  crack  are  pure  and  only  sprinkled 
with  hardening  water  which  has  penetrated,  failure 
may  have  been  caused  by  the  use  of  too  cold  water, 
or  to  a  forging  strain  in  the  tool  which  has  not  been 
removed  by  annealing.  By  the  use  of  warmer 
water  or  another  hardening  fluid  (oil  or  tallow),  or 
by  carefully  annealing  the  tool,  this  defect  may 
readily  be  overcome. 

If  the  surfaces  of  the  crack  show  a  partially  or 
entirely  dark  (brown-red)  color,  the  failure  is  due  to 
defective  material,  the  dark  coloration  of  the  frac- 
ture being  caused  by  oxidation  of  the  steel  in 
heating. 

2.  Flat  tools,  such  as  knives,  etc.,  or  tools  spreading  out 

to  a  broad,  sharp  edge,  such  as  chisels,  drills,  etc., 
show,  after  hardening,  curved  cracks  on  the  corners 
and  back  of  the  edges.  This  is  an  indication  of  un- 
even heating  or  over-heating  of  the  corners  and 
edges. 

3.  The  corners,  edges  and   teeth  of  larger  tools  which 


134  TOOL-STEEL. 

have  been  hardened  in  their  entirety  separate  dur- 
ing or  after  hardening.  If,  with  an  otherwise  cor- 
rect hardening  process,  the  fracture  shows  a  coarse 
structure,  partial  over-heating  is  the  cause  of  the 
failure,  but  if  the  fracture  shows  a  fine  structure, 
failure  is  due  to  incorrect  cooling. 

4.  Tools  cracked  from  the  interior  have  been  incorrectly 

cooled  if  the  surfaces  of  the  crack  when  laid  bare 
show  a  thoroughly  coherent  structure.  If  the  fail- 
ure has  been  due  to  a  pipe  or  other  flaws  in  the  in- 
terior of  the  steel,  it  may  be  recognized  on  the 
surfaces  of  the  crack  when  laid  bare. 

5.  When    cracks    or   separation    of    corners,    etc.,    are 

noticed  on  one  side  of  a  symmetrical  tool,  it  is  indi- 
cative of  uneven  heating  in  hardening. 

6.  Edge   cracks    running   vertically    to    the   edges   and 

showing  sides  of  a  dark  and  black  color  occur  only 
in  burnt  steel. 

If  the  structure  of  the  steel  is  coarse  and  of  a 
white  glistening  color,  the  tool  has  been  burnt  in 
hardening ;  if  the  structure  is  coarse-grained  but 
shows  little  lustre,  the  steel  has  been  burnt  in  one 
of  the  operations  previous  to  hardening. 

7.  If  hardened  tools  show  ail  uneven  degree  of  hardness, 

they  have  been  unevenly  heated  for  hardening, 
or  unevenly  cooled  by  not  having  been  sufficiently 
moved  about  in  the  hardening  fluid,  or  more  cooled 
by  it  on  one  side.  Tools  which  have  been  cooled 
only  for  a  short  time  and  then  allowed  to  become 
cold  while  in  contact  with  the  walls  of  the  cooling 
vessel,  are  apt  to  be  soft  on  the  places  of  contact. 


DEFECTS    OF    HARDENED    TOOLS.  135 

8.  When   tools  show   a   uniform    degree    of  insufficient 

hardness  it  is  more  seldom  due  to  too  slight  heating, 
but  rather  to  an  unsuitable  hardening  fluid,  and 
perhaps  also  to  too  small  a  quantity  of  the  latter. 

With  the  use  of  a  lower  hardening  temperature 
and  in  hardening  larger  tools,  cooling  fluids  acting 
with  greater  intensity  should  be  employed,  and  water 
covered  with  oil,  pure  oil  or  fat  should  be  avoided. 

9.  Soft  spots  in   hardened   tools  are  formed  when  coal 

containing  sulphur  is  used  for  heating.  However, 
such  spots  are  also  formed  when  the  hot  tool  is  too 
slowly  plunged  in  the  cooling  fluid,  and  the  latter 
by  being  dashed  upwards  causes  here  and  there  soft 
spots. 

10.  When  the  surface  of  a  hardened  tool  is  entirely  cov- 

ered with  a  thin  soft  skin,  which  to  a  slight  depth 
can  readily  be  attacked  with  a  file,  the  tool  has  been 
too  slowl}7  heated  in  hardening  and  superficially 
decarbonized.  After  removing  the  soft  skin  by 
grinding,  the  tool,  as  a  rule,  possesses  a  sufficient 
degree  of  hardness  to  permit  its  use,  but  its  cutting 
power  is  of  course  considerably  less  than  that  of  a 
well  hardened  tool. 

11.  Tools  which  have  been   roasted  or  baked  and  much 

decarbonized  in  any  of  the  operations  previous  to 
hardening,  do  not  acquire  any  degree  of  hardness 
whatever.  The  fracture  of  the  steel  shows  towards 
the  edges  dark  streaks  of  dense  lustreless  structure. 

12.  The  defects  due  to  the  tools  which  serve  for  handling 

the  steel  in  hardening  have  already  been  discussed 
on  p.  86. 


136  TOOL-STEEL. 

In  case  there  is  a  doubt  or  uncertainty  about  the  pro- 
cesses of  working  to  be  employed  as  regards  the  quality 
and  degree  of  hardness  of  the  steel  to  be  used  or  the  pur- 
pose for  which  it  is  to  be  employed,  it  is  advisable  to  apply 
for  hardening  directions  to  the  source  from  which  the  steel 
has  been  obtained. 

By  an  immediate  inspection  of  the  hardened  tool  only 
part  of  the  mistakes  made  in  hardening  or  previous  opera- 
tions can  be  found  out.  The  defects  noticed  in  using  the 
tools  are  generally  confined  to  a  deficiency  in  the  degree  of 
hardness.  Such  defects  are  generally  due  to  the  fact  that 
the  degree  of  hardness  has  been  incorrectly  chosen,  and 
partially  to  faulty  hardening.  If  a  tool  is  found  to  possess 
insufficient  cutting  power,  it  may  be  the  fault  of  its  not 
being  hard  enough  as  well  as  of  its  being  too  hard  and 
brittle.  Microscopical  particles  break  out  of  the  edges  of 
tools  which  have  become  brittle  in  hardening  and  the 
edges  soon  become  dull,  the  impression  being  the  same  as 
when  too  soft  steel  becomes  rapidly  dull.  If  it  is  attempted, 
as  is  frequently  done,  to  remedy  this  defect  by  still  more 
intense  hardening,  the  result  is  the  reverse.  To  give  the 
tool  better  edge-holding  power,  it  suffices,  as  a  rule,  to 
remove  the  superficial,  more  brittle,  layer  by  grinding. 
When  the  edge  has  to  be  renewed  a  lower  hardening  tem- 
perature should  be  tried  and  less  intense  cooling.  Should 
the  efficiency  of  the  tool  remain  unsatisfactory,  it  may  be 
supposed  that  the  degree  of  hardness  selected  has  been  too 
low. 

That  with  cutting  tools  of  hard  steel  the  highest  attain- 
able degree  of  hardness  does  not  always  yield  the  greatest 
efficiency  may  be  seen  from  the  experiments  made  at 


DEFECTS    OP    HARDENED    TOOLS. 


137 


Bismarckhuette,  the  results  of  which  are  given  in  the  table 
below. 

For  these  experiments  several  cutters  were  made  from 
one  and  the  same  bar  of  steel,  and  one-half  of  them  were 
carefully  hardened  from  a  bright  red  heat  in  water  of 
64.4°  F.,  and  without  further  tempering  tested  under  the 
same  conditions.  The  average  efficiency  of  these  was  re- 
duced to  the  figure  100.  The  remaining  half  of  the  cutters 
were  heated  to  not  so  bright  a  red  heat,  hardened  in  water 
of  64.4°  F.,  until  all  heat  had  disappeared,  plunged  in  boil- 
ing water  and  allowed  to  cool  in  it. 

The  efficiency  was  better  throughout,  namely  : 


Degree  of  hardness  of  the  cutters. 

Intensely 
hardened 
in  water. 

Hardened 
in  water, 
tempered 
in  boiling 
water. 

No.  1.  Steel  with  0.85  %  carbon. 
No.  2.  Steel  with  1.32  %  carbon. 
No.  3.  Special  steel  with  1.57  % 

100 
100 

100 

112 
118 

135 

carbon  and  4.5  % 

The  test  was  made  upon  annealed  cast-steel  of  the  same 
degree  of  hardness  as  that  of  the  cutters. 

It  will  be  seen  from  the  increase  in  efficiency,  up  to  as 
much  as  35  per  cent.,  that  by  a  suitable  process  of  cooling 
an  appreciable  gain  in  time  and  efficiency  can  be  attained. 
A  defect  frequently  observed  on  very  hard  cutting  tools 
consists  in  cracks  which  are  formed  on  the  surface  after 
previous  grinding  off  of  the  worn-out  edge  and  cause  the 
uppermost  layer  of  steel  to  peel  off  in  the  form  of  laminae, 


138  TOOL-STEEL. 

but  which  may  also  run  in  various  directions  throughout 
the  entire  tool.  Defective  steel  is,  as  a  rule,  blamed  for 
these  cracks,  but  this  is  generally  a  mistake,  because  they 
are  formed  by  grinding  upon  hard,  rapidly-revolving 
emery  wheels,  even  if  the  latter  run  wet. 

These  emery  wheels  attack  the  surface  of  the  steel,  and 
the  area  pressed  against  them  being  suddenly  heated  to  a 
high  temperature,  a  change  in  volume  takes  place,  in  con- 
sequence of  which  cracks  are  formed.  With  such  emery 
wheels  rapid  cooling  by  the  water  is  effected  after  the  tool 
has  been  pressed  against  them,  but  remains  ineffective  dur- 
ing that  operation. 

The  above-described  phenomenon  is  more  frequently  ob- 
served when  dealing  with  hard  cutting  tools  than  with 
tools  of  a  less  degree  of  hardness. 

In  using  tools  with  engraved  surfaces,  for  instance, 
stamping  tools,  which  work  under  high  pressure,  the  sharp 
edges  will  frequently  be  observed  to  crumble.  This  is  an 
indication  of  too  high  a  degree  of  hardness,  and  can  be 
remedied  by  laying  for  a  short  time  a  hot  metal  plate  upon 
the  tools  before  using  them. 

The  corners  and  edges  of  tools  which,  while  in  use,  are 
exposed  to  a  high  degree  of  heating,  readily  become  notched 
in  the  commencement  of  the  operation.  In  consequence 
of  heating,  a  superficial  change  in  the  volume  of  the  steel 
takes  place.  The  steel  endeavors  to  contract,  which  is  pre- 
vented by  the  layers  underneath,  which  are  still  cold,  the 
consequence  being  the  formation  of  numerous  fine  cracks, 
and  the  tool  becomes  notched.  To  avoid  this  defect,  the 
tool  should  be  heated  before  use,  and  the  more  so  the 
higher  the  degree  of  heating  to  which  it  is  exposed  during 


DEFECTS    OF    HARDENED    TOOLS.  139 

the  work.  Tools  on  which  slighter  demands  are  made  are 
heated  to  hand-warm,  and  those  exposed  to  a  higher  degree 
of  heating  are  heated  throughout  to  a  uniform  temperature 
in  boiling  water. 

The  above-recommended  process  may  be  used  to  advant- 
age with  dies  and  cutters,  as  well  as  with  tools  which  while 
in  use  are  heated  by  blow  and  shock. 

Incorrect,  sharply-defined  hardening  causes  the  tool  while 
in  use  to  break  off  short,  and  this  defect  can  then  be  readily 
noticed. 

The  drawbacks  due  to  too  high  a  demand  made  on  the 
tools  or  by  too  suddenly  engaging  them  become  manifest 
by  the  destruction  of  the  tools  themselves  or  of  their  edges, 
and  the  causes  of  this  may  be  readily  recognized  and 
avoided. 

Without  entering  into  a  further  explanation  of  the  de- 
fects and  blemishes  which  may  originate  in  hardening, 
tempering  and  in  using  tools,  it  may  be  recommended  to 
subject  tools  which  appear  faultless  in  hardening,  but  prove 
defective  in  use,  to  as  careful  an  examination  as  if  they  had 
been  found  defective  in  hardening.  Such  examinations 
serve  to  increase  the  experience  of  the  hardener. 


140  TOOL-STEEL. 

XIX. 

IMPROVING  THE  PROPERTIES  OF  STRENGTH 
OF  STEEL. 

THE  object  of  improving  the  properties  of  strength  of 
steel  is  to  give  it  special  elasticity,  strength,  or  toughness. 
In  most  cases  the  production  of  the  greatest  attainable 
strength  and  toughness  is  aimed  at. 

As  has  been  mentioned  in  a  previous  chapter,  the  co- 
hesive power  of  the  structure  of  steel,  which  determines  its 
strength  and  toughness,  undergoes  considerable  changes  in 
the  operations  of  hardening,  letting  down,  and  by  manipu- 
lation. By  the  operation  of  annealing  the  strength  of  steel 
is  diminished  and  its  toughness  increased.  By  working 
steel  at  a  low  temperature  its  strength  is  increased,  but  its 
toughness  decreased  even  to  brittleness. 

Steel  rolled  or  forged  at  a  high  temperature  possesses  less 
strength  and  greater  toughness  than  steel  worked  at  a  low 
temperature.  When  it  is  of  importance  to  give  to  steel  for 
structural  purposes  uniform  properties  of  strength  through- 
out, it  must  be  worked  in  a  positively  even  temperature. 
Even  properties  of  strength  may  be  imparted  to  steel  of 
varying  quality  by  a  suitable  adaptation  of  the  working 
temperature. 

By  the  operation  of  hardening,  the  strength  of  iron 
which  is  not  capable  of  being  hardened  is  essentially  in- 
creased and  its  toughness  reduced.  Steel,  which  is  capable 
of  being  hardened,  loses  in  strength  and  all  its  toughness ; 
it  becomes  brittle. 

By  the  operation  of  tempering,  the  strength  and  tough- 
ness of  steel  are  up  to  a  certain  limit  increased. 


PROPERTIES  OF  STRENGTH  OF  STEEL.        141 

If  letting-down  is  continued  above  the  gray  temper  color 
up  to  the  hardening  temperature,  the  steel  passes  through 
the  various  stages  of  strength,  the  latter  increasing  to  a 
certain  tempering  temperature,  and  then  it  gradually  de- 
creases until  it  acquires  the  lowest  degree,  when  a  complete 
annealing  temperature  has  been  attained.  The  toughness 
of  the  steel  increases  thereby  constantly. 

If  steel  is  hardened  and  then  heated  to  different  temper- 
atures and  allowed  to  cool,  it  will  possess  different  degrees 
of  strength  and  toughness. 

Similar  phenomena  may  be  observed  on  steel  which  has 
been  cooled  from  the  hardening  temperature  in  fluids  of 
different  degrees  of  heat,  for  instance,  in  boiling  water  or 
in  molten  lead. 

The  most  useful  methods  for  improving  and  regulating 
the  properties  of  strength  of  steel  by  a  suitable  combination 
of  hardening  and  reheating  are  patented,  and  are  practically 
applied  in  the  manufacture  of  steel  weapons,  for  instance, 
cannon,  and  are  still  more  widely  employed  in  the  manu- 
facture of  machine  parts  on  which  great  demands  are 
made,  railroad  material,  etc. 

For  the  application  of  this  process  the  construction  of 
suitable  appliances  is  required,  as  well  as  extensive  control 
of  the  properties  of  strength  attained  by  means  of  machines 
serving  for  testing  materials. 

For  the  manufacture  of  tools  and  their  use,  the  methods 
for  improving  the  properties  of  strength  of  steel  are  but  of 
secondary  importance ;  they  are  unconsciously  practiced 
by  annealing,  hardening  and  tempering  the  tool. 


APPENDIX. 


IN  works  in  which*the  manufacture  of  tools  is  carried  on 
on  a  large  scale,  the  output  of  large  quantities  of  products 
of  a  similar  nature  comes,  as  a  rule,  only  into  question. 
The  appliances  which  serve  for  the  various  operations  in 
forging,  hardening,  tempering,  etc.,  are  established ;  the 
methods  of  working  are  the  result  of  experience  and  the 
necessity  of  avoiding  every  kind  of  loss,  and,  as  a  rule, 
have  been  properly  selected.  The  same  holds  good  as  re- 
gards the  skill  and  experience  of  the  workmen  who  carry 
on  the  various  operations  in  the  manufacture  of  tools,  and 
on  whose  attention,  by  reason  of  a  suitable  division  of 
labor,  but  a  limited  demand  is  made. 

The  toolsmith  or  locksmith  is,  however,  confronted  by 
entirely  different  conditions.  Daily,  nay  hourly,  demands 
are  made  on  him  in  reference  to  the  construction  of  tools,  as 
is  the  case  in  establishments  where  many  different  kinds  of 
tools  are  required  for  carrying  on  the  work. 

In  such  establishments  as,  for  instance,  iron  works, 
machine  shops,  etc.,  the  rapid  and  uninterrupted  progress 
of  the  various  operations  depends  largely  on  tools  of  fault- 
less construction.  Varied  demands  are  made  on  the  fore- 
man and  workmen  entrusted  with  this  work,  and  to  satisfy 
these  demands,  extensive  knowledge  and  experience  are 
required,  as  well  as  the  necessary  appliances.  In  practice 
such  appliances  are  unfortunately  seldom  found,  they  being, 

(142) 


APPENDIX.  143 

as  a  rule,  so  primitive  as  to  prove  rather  a  hindrance  than 
an  advantage  in  the  manufacture  of  effective  tools. 

The  appliances  for  the  different  operations  in  the  manu- 
facture of  tools  as  far  as  they  refer  to  the  treatment  of  steel 
in  heating  and  hardening  have  on  the  whole  been  described 
in  the  previous  chapters.  The  process  of  working  to  be 
observed  in  these  operations  depends  on  the  quality  or  hard- 
ness of  the  steel  and  the  purpose  for  which  the  tool  is  to 
be  used. 

Below,  the  mode  of  working  to  be  observed  in  forging, 
annealing,  hardening,  and  tempering  a  number  of  tocjs 
frequently  called  for  will  be  explained. 

1.  HAND  CHISELS. 

Quality  of  steel  to  be  used :  For  locksmith's  chisels  for  hard 
materials  which  are  to  hold  their  edges  under  light  blows 
with  the  hammer,  medium  hard  steel  should  be  used  ;  for 
chisels  to  be  worked  by  compressed  air,  hard  steel. 

For  chisels  to  be  used  upon  soft  materials  under  sharp 
blows  of  a  heavy  hammer,  very  lough  steel  should  be 
used  ;  also  for  chisels  with  long  and  sharply  stretched-out 
edges. 

Forging :  At  the  utmost  in  a  bright  red  heat. 

Hardening :  Heating  to  a  cherry-red  heat,  which  should 
extend  to  about  0.59  to  0.78  inch  back  of  the  edge,  and 
then  backward  in  gradual  transition.  Plunging  the  edge 
about  0.78  to  1.18  inches  inches  deep  in  water  of  64°  to 
68°  F.,  moving  it  about,  then  lightly  up  and  down  until 
all  heat  is  quenched. 

For  tempering  the  chisel  is  rubbed  bright,  the  progress  of 
the  temper  color  followed  up,  and  after  the  appearance  of 


144  TOOL-STEEL. 

the  violet  or  blue  color  it  is  fixed  by  plunging  the  chisel  in 
water,  which,  if  required,  may  be  repeated,  or  in  oil  or  soap 
water. 

Chisels  which  have  to  be  very  tough,  are  heated  twice  to 
the  temper  color,  the  first  color  being  rubbed  ofl'  and  heat- 
ing repeated. 

2.  HOT  AND  COLD  CHISELS. 

Quality  of  steel  to  be  used :  For  hot  chisels,  medium  hard  ; 
for  cold  chisels,  tough. 

Forging,  hardening,  and  tempering,  same  as  for  hand 
chisels. 

If  hot  and  cold  chisels  are  to  be  subjected  to  particularly 
powerful  blows,  it  is  best  to  use  a  good  quality  of  weldable 
steel  to  facilitate  repairing  of  the  heads,  which  are  apt  to 
fray  and  split,  and  to  heat  the  edges  only  to  a  dark  yellow 
or  brown-red  temper  color. 

3.  RIVET-CHISELS. 
(For  cutting  off  rivet  heads.) 

These  are  treated  in  the  same  manner  as  hot  or  cold 
chisels. 

4.  CENTER- BITS. 

Quality  of  steel :  Medium  hard  to  hard. 

Forging :  Good  cherry -red  heat,  if  possible  with  the  use 
of  a  charcoal  fire. 

Hardening:  After  obtaining  a  uniform  cherry-red  heat, 
extending  to  about  0.39  inch  back  'of  the  edge  and  then 
gradually  decreasing,  thinner  bits  are  completely  cooled  in 
water  and  heated  to  a  yellow  temper  color  by  heating  the 
tools  back  of  the  edge. 


APPENDIX.  145 

Broad,  thick  bits  are  hardened  in  the  same  manner  as 
hand  chisels  and  tempered  from  the  back  end  with  the 
assistance  of  the  fire  if  the  heat  stored  in  the  tools  is  not 
sufficient  for  the  purpose. 

5.   TURNING  KNIVES  AND  PLANING  KNIVES. 

Quality  of  steel :  Hard  to  very  hard. 

Forging:  Cherry-red  heat  with  the  exclusive  use  of  char- 
coal. By  long  continued  forging,  the  steel  readily  breaks 
up,  as  well  as  by  too  powerful  blows  with  the  hammer. 
After  forging,  turning  and  planing  knives  should  always 
be  allowed  to  become  cold. 

Hardening :  Slow  heating,  with  the  use  of  little  blast,  to 
a  scant  cherry-red  heat,  extending  to  about  0.78  inch  back 
of  the  edge  and  then  gradually  decreasing.  Quenching  in 
water  by  immersing  to  a  depth  of  about  1.18  inches,  and 
moving  about,  and  up  and  down.  When  cool,  rub  off  and 
heat  to  a  full  yellow  temper  color  and  finally  cool  slowly 
by  successive  immersions  for  a  short  time  in  warm  water. 

6.    ROLL-TURNING    KNIVES 

X  of  accompanying  cross-section. 

Quality  of  steel:  Very  hard,  special  steel. 

Forging:  Grooved  roll  turning  knives  are  cut  off  from 
profile  steel  or  shaped  from  the  whole  steel. 

Hardening :  The  highest  attainable  degree  of  glass  hard- 
ness is  demanded,  which  is  not  modified  by  letting-down. 

Heating  for  hardening  should  not  be  effected  in  the  open 

fire  but  if  possible  in  a  muffle  or  a  hardening  furnace,  and 

should  at  first  be  done  slowly  to  a  dark  cherry-red,  and 

then  rapidly  to  not  too  bright  a  cherry -red,  heat.     When  the 

10 


146  TOOL-STEEL. 

latter  heat  has  been  attained,  the  tool  is  quenched  until 
entirely  cold  in  pure  water,  or  better  in  salt  water  or  acidu- 
lated water. 

The  cold  knife  is  then  laid  in  hot  sand  or  hot  water  and 
allowed  slowly  to  cool  in  it.  With  grooved  turning  knives 
hardened  in  their  entirety,  there  is  great  danger  of  crack- 
ing, the  latter  occurring  frequently,  but  there  are  no  sure 
means  of  preventing  it. 

7.  SCREW  TAPS. 

Quality  of  steel :  For  small  taps,  tough  to  tough  hard  ;  for 
larger  taps,  tough  hard  to  medium  hard. 

Forging :  Screw  taps  are  turned  and  milled  from  the  solid 
piece. 

Hardening :  Taps  worked  singly  are  heated  for  hardening 
in  an  open  charcoal  fire  by  bringing  the  charcoal  to  a  glow 
with  the  aid  of  considerable  blast,  then  stopping  the  latter 
and  bringing  the  tap  to  a  dark  cherry-red  heat  in  the  quiet 
fire  thus  obtained.  Further  heating  to  the  hardening  tem- 
perature is  rapidly  effected  with  the  use  of  the  blast. 

Taps  almost  cylindrical  in  shape  are  plunged  vertically, 
twisted  portions  foremost,  in  water,  and  very  tapering  taps 
head  foremost,  the  latter  being  allowed  to  cool  throughout, 
while  the  former  must  be  withdrawn  far  enough  for  the 
head  to  remain  soft.  When  the  heat  is  quenched  the  taps 
are  withdrawn  from  the  water — the  latter  still  evaporating 
on  the  surfaces — then  let  down  from  the  interior  to  from 
yellow  to  brown  temper  color,  and  finally  cooled  entirely. 

When  a  larger  number  of  small  taps  are  to  be  hardened 
at  one  time  they  are  packed  in  a  sheet-iron  box  between 
powdered  charcoal  and  charred  leather,  and  heated  as  pre- 


APPENDIX.  147 

viously  described.  For  hardening,  the  taps  are  singly  taken 
from  the  box. 

In  the  open  fire,  large  taps  can  only  be  brought  to 
the  hardening  temperature  after  long-continued  roasting, 
whereby  superficial  decarbonization  frequently  takes  place 
and  the  teeth  remain  soft.  To  overcome  this  drawback 
they  are  heated  for  hardening  in  the  hardening  furnace, 
the  teeth  having  been  previously  protected  by  hardening 
paste,  or  heating  for  hardening  is  effected  in  a  muffle. 

If  heating  in  an  open  fire  cannot  be  avoided,  packing  in 
a  sheet-iron  box  between  charcoal  and  hoof  meal  should  be 
resorted  to.  By  letting  down  from  the  interior  the  teeth 
of  large  pieces  would  be  struck  too  late  by  the  advancing 
heat,  and  for  this  reason  the  tools  should  be  cooled  to  as 
great  a  depth  as  possible,  then  allowed  slowly  to  cool  in  hot- 
sand  or  hot  water,  so  as  to  avoid  as  much  as  possible  a 
severance  of  teeth  and  corners. 

If  letting  down  small  taps  during  hardening  is  not  desir- 
able, they  are  placed  immediately  after  cooling  in  hot  sand 
or  hot  water.  Letting  down  is  then  effected  by  heating 
the  heads  in  a  dim  gas  flame  or  spirit  flame. 


8.  SCREW-DIES. 

Quality  of  steel: :  The  same  as  for  screw  taps. 

Hardening:  Heating  for  hardening  is  effected  in  the 
same  manner  as  given  for  screw  taps.  Hardening  and 
letting  down  are  done  as  follows : 

The  shape  of  screw-dies  does  not  allow  of  letting  down 
from  the  interior,  and  in  hardening  they  must  therefore  be 
entirely  cooled.  To  decrease  the  danger  of  cracking  they 
should  be  cooled  in  a  mild  hardening  agent — molten 


148  TOOL-STEEL. 

tallow — or  in   water  until   all   heat  has  disappeared,  and 
then  allowed  completely  to  cool  in  oil. 

Sharply  hardened  screw-dies  are  let  down  at  a  brown-red 
temper  color,  and  screw-dies  of  a  less  degree  of  hardness  at 
a  yellow  temper  color,  by  laying  them  upon  a  weak  char- 
coal fire,  or  better  upon  red-hot  pieces  of  iron. 

9.  BROACHES. 

Quality  of  steel :  Same  as  for  screw  taps. 
Hardening :  Same  as  for  screw  taps. 

10.  SPIRAL  DRILLS  FOR  METAL. 

Quality  of  steel :  Medium  hard  to  hard. 

Hardening:  Heating  and  hardening  are  effected  in  the 
same  manner  as  with  screw  taps,  but  for  the  sake  of  uni- 
form heating,  in  the  muffle,  hardening  furnace  or  in  molten 
lead  (salts).  The  difficulty  of  hardening  the  entire  drill 
lies  in  the  fact  that  it  must  not  become  much  or  at  all 
distorted. 

In  hardening  from  the  open  fire,  if  the  use  of  the  latter 
cannot  be  avoided,  uneven  heating  is  prevented  by  hard- 
ening the  drill  only  ^  to  J  of  its  length  if  it  is  to  be  used 
for  boring  not  very  deep  holes.  Heating  a  shorter  length 
results  in  an  even  hardening  temperature,  gradually  de- 
creasing backward. 

Cooling  is  effected  by  plunging  the  drill  vertically  into 
a  vessel  of  as  great  a  depth  as  possible,  moving  it  up  and 
down  with  a  rotatory  motion.  By"  moving  it  sideways  it 
would  readily  become  distorted  in  consequence  of  uneven 
lateral  cooling. 

The  drill  when  completely  cooled  is  heated  to  a  yellow 


APPENDIX. 


149 


FIG.  63. 


temper  color,  and  while  in  this  state    is   straightened    in 
the  screw  press. 

Saturated  solution  of  common  salt, 
or  of  soda  or  sal  ammoniac,  is  used  as 
cooling  fluid. 

Letting  down  is  effected  upon  heated 
sand  or  over  a  charcoal  fire  in  mod- 
erate glow,  which  can  be  readily  pre- 
pared as  shown  in  Fig.  63. 

11.  CANNON  DRILLS. 
Quality  of  steel,  and  hardening :  Same  as  for  spiral  drills. 

12.  CUTTERS. 

Quality  of  steel:  For  ordinary  cutters  for  soft  metals, 
tough  hard  to  medium  hard  ;  for  cutters  for  hard  metals 
on  which  great  demands  are  made,  medium  hard  to  hard ; 
for  cutters  of  complicated  shape  for  wood  on  which  but 
slight  demands  are  made,  tough  to  soft. 

Hardening :  Slot  and  tenon  cutters  are  hardened  in  the 
same  manner  as  screw-taps  and  broaches. 

Small  cutters  are  heated  in  the  muffle  built  in  the  open 
fire,  as  shown  in  Fig.  3,  or  better  in  the  hardening  or 
muffle  furnace.  If  several  cutters  are  to  be  hardened  at 
one  time,  they  are  packed,  as  described  under  screw-taps,  in 
a  sheet-iron  box  which  is  heated  to  the  hardening  tempera- 
ture. 

The  cutters  are  cooled  singly  by  plunging  in  water  and 
moving  them  about  in  it ;  they  are  then  placed  in  hot  sand 
and  allowed  completely  to  cool  in  it. 

Letting  down  is  effected  by  placing  them  upon  pieces  of 


150  TOOL-STEEL. 

red-hot  iron  of  a  slighter  diameter,  or  by  means  of  a  red-hot 
mandril  pushed  through  the  hole.  Temper  color  for  the 
bore,  violet ;  for  the  teeth,  brown-red. 

Large  cutters  of  a  flat  shape  (J  to  about  J  of  diameter  to 
thickness)  are  hardened  in,  the  same  manner  but  only 
heated — supported  upon  pieces  of  sheet-iron — in  the  hard- 
ening furnace,  but  better  in  the  muffle  furnace.  The  teeth 
are  protected  by  hardening  paste,  or  with  uneven  heating, 
by  scattering  hardening  powder  upon  them. 

If  permitted  by  the  shape  of  the  cutters,  pieces  of  sheet- 
iron  should  be  used  for  protection.  Letting  down  is 
effected  in  the  same  manner  as  with  small  cutters. 

The  teeth  of  large  or  thick  disc  cutters,  when  continued 
on  the  sides,  are  very  much  exposed  to  being  cast  off  in 
hardening  if  special  care  is  not  used  in  heating.  Such 
cutters  should  not  be  cooled  too  long,  but  heated  as  soon  as 
possible  from  the  exterior  by  plunging  them  in  hot  water  or 
covering  with  hot  sand.  Reheating  to  too  high  a  degree  is 
avoided  by  inspection,  repeated  shortly  before  cooling  off. 

Large  cutters,  greater  in  thickness  than  diameter,  are 
seldom  made  in  one  piece  but  divided  as  described  on  p.  78. 
Hardening  of  such  cutters  is  beset  with  special  difficulties, 
and  should  be  effected  as  previously  described. 

Profile  cutters  are  mostly  made  with  backward  tapering 
teeth  ;  the  cracking  of  long  cutters  in  hardening  is  sought 
to  be  prevented  by  their  suitable  division. 

Profile  cutters  with  teeth  which,  as  shown  in  Fig.  64, 
form  sharp  corners  towards  the  surfaces,  are  protected  by 
pieces  of  sheet-iron,  or,  as  shown  in  the  same  sketch,  by 
continuing  the  teeth  in  a  curve,  if  permitted  by  the  use  for 
which  the  cutter  is  intended. 


APPENDIX. 


151 


In  heating,  the  utmost  attention  has  to  be  paid  to  the 
sharp  corners,  and  they  should  be  frequently  cooled  by 
scattering  hardening  powder  upon  them. 

Hollow  cutting  bodies  are  seldom  used.  They  are  hard- 
ened by  means  of  a  powerful  jet  of  water,  which  is  allowed 
to  circulate  in  the  hollow  space. 

For  cooling  cutters,  hardening  water  which  has  been 
repeatedly  used  should  be  selected,  or  solution  of  common 
salt,  or  of  sal  ammoniac.  For  larger  or  very  complicated 

Fm.  64. 


catters  the  hardening  water  is  covered  with  a  layer  of  oil. 
If,  however  the  teeth  on  large  cutters  are  of  a  small  cross 
section  or  slight  height,  the  use  of  a  layer  of  oil  should  be 
avoided,  otherwise  the  steel  may  readily  remain  soft. 

Cutters  for  wood  are  mostly  profile  cutters  of  complicated 
shape,  which  for  this  reason  are  difficult  to  harden  if  the 
tools  are  to  possess  a  full  degree  of  hardness  modified  by 
subsequent  letting  down. 

A  higher  degree  of  hardness  and  greater  capacity  of 
holding  their  edges  than  those  of  wood-working  tools  in 
general  are  seldom  required  for  wood-cutters,  and  hence  as 
a  rule  nothing  more  is  necessary  than  good  spring  hardness. 

Wood-cutters  are  frequently  made  of  very  hard  steel  and 
successfully  used  in  an  unhardened  state.  However,  on 
account  of  its  being  more  easily  worked,  soft  steel  or  steel 
of  good  hardening  quality  is  selected. 


152  TOOL-STEEL. 

If  tough  steel  of  good  hardening  quality  is  used,  it  is 
better  to  harden  it  in  a  mild  cooling  fluid  and  to  use  it 
without  further  letting  down  than  to  give  a  full  degree  of 
hardness  and  then  letting  down. 

Such  cutters  having  been  evenly  heated  to  a  cherry-red 
heat,  are  hardened  in  oil  or  in  tallow  and  allowed  to  cool 
in  it. 

The  method  of  cooling  wood  cutters  of  harder  steel  in 
molten  metals  is  less  known.  For  this  purpose  molten  lead 
(741.2°  F.),  tin  (442.4°  F.),  zinc  (772.6°  F.),  or  a  mixture 
of  a  known  fusing  temperature  is  used,  for  instance, 

Lead 8  parts. 

Tin , 4  parts. 

which  melts  at  446°  F. 

The  cutters  heated  to  a  uniform  bright  cherry-red  heat 
are  plunged,  as  in  ordinary  hardening,  in  the  molten  metal 
allowed  for  a  short  time  to  remain  in  it,  and  then  rapidly 
cooled  in  water. 

Cutters  thus  hardened  possess  a  high  degree  of  tough 
hardness,  sufficient  to  give  them  the  capacity  of  holding 
their  edges  in  working  wood. 

If  a  larger  number  of  cutters  are  to  be  cooled  at  one  time 
in  molten  metal,  a  constantly  even  temperature  is  abso- 
lutely necessary  for  uniform  success,  and  hence  a  pyrometer 
should  be  used. 

13.    PIPE-CUTTERS. 

Quality  of  steel :  Tough  hard  to  medium  hard. 

Hardening :  Inside  cutters  are  hardened  like  broaches ; 
outside  cutters  are  hardened  under  a  descending  water-jet 
which  strikes  the  bore. 


APPENDIX.  153 

14.  PIPE-CUTTING  KNIVES. 
Quality  of  steel :  Tough  hard  to  tough. 
Hardening :   After  uniform   heating  to  cherry-red,   they 
are  hardened  in  oil  and  used  without  further  letting-down. 

15.  MILLING  TOOLS. 

Quality  of  steel :  Soft. 

Hardening :  Small  milling  tools  are  hardened  like  hot 
and  cold  chisels ;  large  milling  tools  are  hardened  under  a 
water  jet  conducted  into  the  cavity. 

Letting  down  is  effected  in  the  same  manner  as  with 
hand  and  hot  and  cold  chisels,  but  may  be  entirely  omitted 
if  a  suitable  quality  of  steel  has  been  used. 

16.  HAMMERS. 
(Hand  hammers,  riveting  hammers,  sledge  hammers,  etc.) 

Quality  of  steel:  As  a  rule,  steel  of  a  slighter  degree  of 
hardness  is  selected  for  these  tools,  which  in  hardening 
does  not  require  letting-down. 

Hardening:  Long  hammers,  the  faces  of  which  can  be 
heated  separately  without  the  heat  reaching  the  face 
already  hardened,  are  heated  and  hardened  like  hot  and 
cold  chisels,  each  face  by  itself. 

Short  hammers  which  for  the  purpose  of  hardening  have 
to  be  heated  in  their  entirety,  are  first  hardened  on  the 
narrow  face  by  plunging  them  1.18  to  1.57  inches  deep  in 
water,  then  withdrawing  them  somewhat  for  allowing  the 
hardening  to  spread,  and  finally,  entirely  quenching  them. 
The  broad  face  retains  sufficient  heat  to  be  hardened  in  a 
similar  manner  in  an  ascending  water-jet,  the  narrow  face 
being  cooled  by  placing  wet  rags  upon  it.  When  the  broad 


154  TOOL-STEEL. 

face  is  hardened  under  a  descending  water-jet,  the  hardened 
narrow  face  is  in  the  meanwhile  plunged  in  a  vessel  filled 
with  water. 

While  hardening  both  faces,  the  center  portion  of  the 
hammer  has  lost  sufficient  heat  to  allow  of  its  being  cooled 
by  repeatedly  plunging  for  a  short  time  in  water. 

17.  HAMMER  SWAGES. 

Quality  of  steel :  Very  tough  to  hard  ;  according  to  the 
purpose  for  which  they  are  to  be  used,  or  to  the  demand 
made  on  them. 

Hardening :  Swages  with  flat  faces  or  elevations  on  them 
are,  for  hardening,  heated  in  the  open  forge-fire  so  that  the 
face  to  be  hardened  is  heated  last.  The  swage  is  placed  in 
the  fire,  the  latter  having  been  brought  to  a  uniform,  ex- 
tensive glow  by  putting  on  a  large  quantity  of  fuel  and 
with  the  use  of  the  blast.  The  swage  with  the  foot  towards 
the  blast  is  brought  into  the  fire  and  allowed  slowly  to 
heat,  the  blast  having  been  shut  off  enough  to  just  main- 
tain the  glow. 

When  the  entire  tool  has  thus  been  brought  to  a  uniform 
dark  cherry-red  heat,  it  is  turned  and  the  face  is  rapidly 
heated  to  the  hardening  temperature,  care  being  taken  not 
to  overheat  the  corners  of  the  swage,  otherwise  they  may 
readily  break  off  in  the  subsequent  hardening. 

During  heating  the  scale  formed  on  the  face  is  scraped 
off  and  hardening  powder  preventing  oxidation  scattered 
upon  it. 

The  sufficiently  heated  tool  is  then  hardened  by  placing 
it,  face  down,  upon  supports  in  a  vessel  into  which  the 
water  enters  in  a  powerful  ascending  jet.  ( See  Figs.  48 
and  51.) 


APPENDIX.  155 

The  swage  is  plunged  1.18  to  1.57  inches  deep  in  water 
until  the  portion  projecting  from  the  water  shows  only  a 
brown-red.  It  is  then  withdrawn  to  from  0.59  to  0.78  inch 
for  the  purpose  of  obtaining  a  gradual  transition  of  the 
hardness,  and  then  allowed  to  cool  completely. 

This  process  is  subject  to  a  modification  if  the  swage  has 
been  made  of  hard,  instead  of  mild,  steel.  Hardening 
is  then  interrupted  after  the  face  has  been  cooled,  the  swage 
is  lifted  from  the  water,  and  after  rubbing  its  surface  bright, 
is  let  down  from  the  interior  to  a  yellow  to  brown-red 
temper  color ;  it  is  then  further  cooled  in  the  above- 
described  manner. 

When  the  face  of  the  swage  is  deeply  engraved  it  cannot 
be  hardened  in  ascending  water,  otherwise  the  depressions 
may  readily  remain  soft.  Hence,  it  is  hardened  under  an 
ascending  water  jet  which  is  uniformly  distributed  over  the 
entire  surface  by  a  rose  of  suitable  form  arid  size,  a  rose  fed 
by  two  supply  pipes  being  to  advantage  used  for  the  pur- 
pose. The  water  must,  of  course,  enter  under  powerful 
pressure.  When  hardening  has  sufficiently  progressed  to 
allow  of  letting  down,  the  supply  of  water  is  shut  off,  and 
after  the  face  has  been  brought  to  the  temper  color,  cooling 
is  continued  until  the  tool  is  cold. 

For  rapidly  running  hammers  working  with  a  weak 
blow,  and  for  swages  with  very  narrow  faces,  hard  steel 
may  be  used.  For  swages  with  broad  faces,  especially 
when  subject  to  vigorous  blows,  steel  as  tough  as  possible 
should  be  employed.  Swages  of  hard  steel  are  more  subject 
to  cracking  in  hardening,  and  also  crack  frequently  while 
in  use. 

Defects   ar£  also    frequently   due  to   bad   usage,   if  the 


156  TOOL-STEEL. 

swages  have  been  incorrectly  set  so  that  they  obliquely 
strike  one  upon  the  other,  or  when  thoroughly  heating 
them  throughout  every  time  before  use  has  been  neglected. 
If  shortly  after  beginning  work  the  surfaces  of  the  swages 
show  fine  cracks  running  vertically  to  the  edges,  or  criss- 
cross cracks,  it  is  generally  due  to  the  fact  of  them  not 
having  been  hardened  to  a  sufficient  depth.  The  steel 
under  the  hard  surface  is  soon  upset,  and  as  the  harder  sur- 
face cannot  follow  the  change  in  form,  it  cracks  in  different 
directions. 

18.  ROUND  AND  CIRCULAR  SHEAR-KNIVES. 
(Roll  Shear-knives.) 

Quality  of  steel :   Tough. 

Hardening :  For  hardening  such  shear-knives  are  heated 
exactly  in  the  same  manner  as  disc  cutters.  Cooling  in  the 
hardening  fluid  is  effected  until  the  knives  are  entirely 
cold,  and  the  hardened  knives  are  then  placed  in  hot  water 
or  in  hot  sand.  In  letting  down  care  must  be  taken  that 
the  cutting  edges  acquire  a  very  uniform  brown-red  temper 
color. 

19.  SHEAR-KNIVES. 

Quality  of  steel:  Tough  steel  is  used  for  long  knives, 
which  are  principally  to  be  used  for  cutting  sheet  metal, 
and  for  short  knives  for  cutting  iron  and  steel,  on  which 
great  demands  are  made.  Small  shear-knives  for  actual 
cutting  are  made  of  tough  hard  to  hard  steel. 

Warm  shear-knives  are  mostly  used  in  the  unhardened 
state. 

Hardening :  Small  shear-knives  are  best  heated  for  this 
purpose  in  the  hardening  or  muffle  furnace.  When  heat- 


APPENDIX.  157 

ing  in  an  open  fire  one  with  two  or  three  tuyeres  should  be 
used,  with  charcoal  as  fuel. 

Narrow  knives  are  gradually  brought  to  a  throughout 
uniform  cherry-red  heat,  care  being  taken  not  to  overheat 
the  corners,  which  otherwise  in  hardening  break  off  in  a 
curved  crack. 

Hardening  is  effected  by  vertically  plunging  in  water. 
With  the  use  of  hard  qualities  of  steel,  holes,  slots,  screw- 
holes,  etc.,  are  filled  with  dry  clay  ;  with  the  use  of  tough 
steel  this  is  not  necessary. 

Broad,  short  knives  are  heated  on  the  edges  to  a  uni- 
form cherry-red  heat,  gradually  decreasing  backward. 
They  are  then  hardened  by  slowly  plunging  them,  edges 
foremost,  in  water,  and  allowed  to  cool  until  the  interior 
heat  suffices  for  the  production  of  the  purple-red  to  violet 
temper  color,  when  they  are  allowed  completely  to  cool  in 
water.  Such  knives  of  very  tough  steel  can,  after  thus 
being  partially  hardened,  be  used  without  letting  down. 

These  knives  may  also  be  hardened  by  heating  them  in 
their  entirety  and  cooling.  Letting  down  is  then  effected 
by  heating  the  backs  in  sand,  lead,  or  in  a  quiet  char- 
coal fire. 

Great  difficulties  are  met  with  in  heating  long  shear- 
knives,  because  heating  has  to  be  very  uniform  in  order  to 
prevent  distortion  in  hardening.  Heating  in  the  open  fire 
is  most  difficult  of  all.  For  this  purpose  fires  with  several 
tuyeres,  one  alongside  the  other,  are  required,  as  well  as 
the  erection  of  a  structure  as  shown  in  Fig.  3,  so  that  the 
heat  may  be  kept  better  together.  Hence  heating  is 
effected  to  better  advantage  in  a  charcoal  furnace  of  simple 
construction,  such  as  shown  in  Fig.  8,  in  which  a  heat 


158 


TOOL-STEEL. 


uniformly  extending  over  the  entire  knife  can  readily  be 
obtained. 

It  has  to  be  borne  in  mind  that  the  knives  must  first  be 
heated  from  the  back,  and  finally  on  the  edges,  so  that  the 
latter  show  the  highest  temperature  before  cooling. 

For  hardening  the  knives  are  caught  on  the  ends  and 
plunged  backs  foremost  in  the  water  and  uniformly  cooled. 

Letting  down  is  effected  in  the  most  simple  manner,  in 
molten  lead,  the  knives  being  immersed  backs  foremost,  or 
in  hot  sand.  When  neither  molten  lead  nor  hot  sand  is 
available,  recourse  may  be  had  to  the  following  device : 

Set  two  rows  of  bricks,  about  5}  inches  apart,  upon  the 
ground,  form  a  grate  by  placing  iron  rods  across  them,  and 
set  two  more  rows  of  bricks  upon  the  grate.  The  structure 
should  be  somewhat  longer  than  the  knives,  and  is  closed 
at  the  ends  by  bricks.  The  device  is  shown  in  Fig.  65. 

Charcoal  brought  to  a  uniform  glow  in  an  open  fire  is 

FIG.  65. 


put  upon  the  grate,  and  the  knives  are  placed  singly,  one 
after  the  other,  backs  foremost,  in  the  charcoal. 

Slight  differences  in  temperature  are  equalized  by  push- 
ing the  knives  back  and  forward  during  heating,  and  un- 
even letting  down  is  prevented  by  cooling  places  which  are 
too  highly  heated  by  means  of  wet  rags. 


APPENDIX.  159 

20.    MACHINE  KNIVES  FOR  CUTTING  PAPER,  KNIVES  FOR 

SPLITTING  LEATHER,  PLANING  AND  CUTTING 

KNIVES  FOR  WOOD. 

Quality  of  steel :  Tough  to  medium  hard. 

Hardening :  The  operations  for  hardening,  heating  and 
letting  down  are  the  same  as  for  hardening  shear-knives. 

Great  care  must  be  observed  in  heating  to  prevent  the 
sharp  edges  from  becoming  overheated,  and  heating  must 
be  very  uniform  to  avoid  distortion  in  hardening.  These 
knives  are  at  the  best  difficult  to  harden.  They  are 
straightened  during  letting  down  at  the  highest  tempering 
temperature. 

While  these  knives  must  not  be  too  hard,  but  should 
possess  great  power  of  keeping  their  edges  for  a  long  time 
when  used  upon  soft  materials,  it  is  preferable  to  harden 
them  in  tallow  or  train  oil,  the  danger  of  warping  or  crack- 
ing being  thereby  considerably  reduced. 

21.  STAMPING  KNIVES 

for  stamping  out  of  leather  (soles  and  heels),  paper, 
paste-board,  bristol-board,  etc, 

Quality  of  steel :  A  good  quality  of  weldable  cast  steel  or 
weld-steel. 

Hardening  :  For  this  purpose  the  knives  are  best  brought 
in  the  muffle  to  a  good  cherry-red  heat,  the  edges  being 
previously  protected  with  a  hardening  paste,  and  when  a 
uniform  hardening  temperature  has  been  attained,  they  are 
cooled,  backs  foremost,  in  oil  or  tallow. 

Letting  down  to  a  yellow  or  violet  temper  color  is  effected 
by  placing  the  knives  upon  their  backs  in  hot  sand,  lead, 
or  upon  red-hot  iron  plates. 


160  TOOL-STEEL. 

22.  CIRCULAR  KNIVES. 
(Simple,  straight  and  plate  knives.) 

Quality  of  steel:  Tough  to  tough  hard. 

Hardening :  Small  circular  knives  are  brought  in  the 
muffle  to  a  uniform  cherry-red  heat  and  hardened  in 
tallow. 

Letting  down  is  effected  in  the  same  manner  as  with 
round  shear-knive's.  Circular  knives  of  large  diameter  are 
brought  for  the  purpose  of  hardening  to  a  uniform  cherry- 
red  heat,  care  being  taken  to  get  the  heat,  if  possible,  last 
on  the  curved  edges  of  plate  knives,  and  to  see  that  the 
heat  is  as  uniform  as  possible,  otherwise  distortion  is  un- 
avoidable. 

For  hardening,  use  a  narrow  long  vessel  with  holes  in 
the  sides  for  fixing  a  crank  shaft  upon  which  the  knife  to 
be  hardered  is  stuck.  The  knife  should  dip  in  the  cooling 
fluid  as  far  as  it  is  to  be  cooled,  and  is  then  hardened  by 
rapidly  revolving  it.  To  attain  a  uniform  transition  from 
the  hardened  edge  towards  the  centre,  water  covered  to  a 
suitable  depth  with  oil  is  used  as  cooling  fluid. 

23.  PUNCHES  AND  DIES. 

Quality  of  steel :  For  the  punches  somewhat  harder  steel, 
namely,  tough  hard  to  medium  hard,  than  for  the  dies  is 
used  :  for  the  latter,  tough  hard  to  tough. 

Forging  and  annealing :  In  forging  punches  and  dies  and 
stamps,  overheating  of  the  working  edges  and  corners  must 
be  carefully  guarded  against,  it  being  especially  injurious. 
The  object  of  annealing  is  to  facilitate  the  working  of  the 
steel,  but  to  avoid  partial  decarbonization  of  the  surfaces 
and  edges  these  tools  should  be  annealed  packed  in  a  box 
between  powdered  charcoal  or  hoof  meal. 


APPENDIX.  161 

Hardening :  In  hardening  the  punches  it  must  be  borne 
in  mind  that  they  are  almost  exclusively  engaged  on  the 
edges  and  must  be  capable  of  holding  them  for  a  long 
time.  Hence,  for  hardening  they  are  first  heated  from  the 
rear,  and  as  soon  as  the  upper  portions  show  a  uniform 
dark  cherry-red  heat,  the  front  portions  are  brought  to 
the  hardening  temperature. 

Hardening  is  effected  in  the  same  manner  as  with  turn- 
ing knives  by  cooling  to  a  certain  depth — as  far  as  the 
punch  is  to  be  hard — and  letting  down  from  the  rear  of  the 
red-hot  tool  to  dark  yellow  to  violet  temper  color.  More 
seldom  the  entire  punch  is  cooled  off,  and  letting  down 
effected  by  reheating  the  back  portion. 

The  dies  are  mostly  made  of  mild  steel  and  of  but  a 
slight  height.  Low  dies  are  heated  for  hardening  to  a  uni- 
form cherry-red  heat,  it  being  advisable  to  protect  the  in- 
ternal cutting  edges  from  decarbonization  by  coating  them 
with  hardening  paste,  or  from  overheating,  by  scattering 
hardening  powder  upon  them.  The  die  is  then  hardened 
in  its  entirety  by  plunging  it  vertically  in  the  hardening 
fluid. 

When  made  of  very  mild  steel  the  die  is  used  with  its 
full  hardness,  but  when  made  of  harder  steel  it  has  to  be 
let  down,  which  is  effected  by  placing  it  upon  a  red-hot 
iron  plate  until  the  yellow  temper  color  appears  upon  the 
surface. 

High  dies  are  not  hardened  in  their  entirety,  but  by  a 
descending  water-jet  which  must  strike  with  particular 
force  the  surfaces  and  interior  openings.  The  process  is 
the  same  as  for  swages. 

Crumbling  of  the  edges  of  dies  in  use,  which  is  frequently 
11 


162  TOOL-STEEL. 

observed,  is  due  to  too  high  a  degree  of  hardness;  the  for- 
mation of  fine  cracks  is  caused  by  the  hardness  not  pene- 
trating to  a  sufficient  depth. 

24.  STAMPS  AND  DIES. 

These  differ  from  punches  and  dies  in  that  they  have 
not  a  cutting  effect,  but  transfer  by  pressure  a  more  or  less 
sharp  engraving  to  metals  laid  between  them. 

Quality  of  steel :  Medium  to  very  hard,  special  qualities 
being  particularly  serviceable  for  this  purpose. 

Hardening :  The  duty  demanded  from  the  stamp  and  the 
die  being  the  same,  they  are  made  of  steel  of  the  same  de- 
gree of  hardness.  Both  are  also  hardened  in  the  same 
manner. 

In  heating  stamps  and  dies  care  must  be  taken  that  the 
engraved  surfaces  do  not  become  decarbonized  or  covered 
with  scale.  However,  since  these  pieces  have  mostly  large 
cross-sections  and  must  be  hardened  in  their  entirety,  they 
have  to  be  heated  for  some  time  and  there  is  always  danger 
of  decarbonization  as  well  as  of  the  formation  of  scale. 
This  is  prevented  by  heating  the  tools  packed  in  a  box 
between  horn  and  hoof  shavings.  With  long-continued 
heating  the  cementing  action  of  charcoal  or  charred  leather 
is  too  great,  and  the  use  of  these  agents  should,  therefore, 
be  avoided. 

The  hardening  process  itself  has  been  described  on  p.  76. 

25.  PUNCHES  AND  DIES  FOR  PERFORATING  HOLES  IN 

METALS. 

Quality  of  steel :  For  dies,  mild,  tough  to  tough  hard  steel. 
For  punches  to  be  used  upon  thin  metals,  tough  hard  to 


APPENDIX.  163 

medium  hard  steel ;  for  punches  for  thick  articles  of  hard 
metals,  medium  hard  to  hard  steel,  and  special  qualities 
serving  for  this  purpose.  Generally  speaking,  what  has 
been  said  in  reference  to  forging  and  hardening  of  punches 
and  dies,  also  applies  to  these  tools.  It  is,  however,  neces- 
sary to  say  something  in  reference  to  the  treatment  of 
punches  on  which  great  demands  are  made,  for  instance, 
in  the  preparation  of  railroad  material  in  punching  fish- 
plates, bed-plates,  etc. 

Instead  of  forging  the  working  part  of  the  punch,  it  is 
better  to  turn  it  and  give  it  its  final  shape  by  filing.  In 
forging,  the  portion  of  the  punch  on  which  the  greatest 
demands  are  made,  is  readily  overheated,  and  in  upsetting, 
as  is  mostly  done  for  the  purpose  of  obtaining  a  broader 
surface  of  application,  the  cohesive  power  of  the  structure 
is  injured,  which,  when  the  tool  is  used,  results  in  the  steel 
peeling  off  concentrically.  For  hardening,  the  punch  is 
heated  in  an  open  fire  with  the  exclusive  use  of  charcoal, 
or  better  in  a  muffle.  The  thicker  portion  is  first  heated 
and  brought  to  a  cherry-red  heat,  and  then  the  portion  on 
which  the  greatest  demand  is  made.  Overheating  of  the 
edges  and  corners  must  be  carefully  avoided,  and  should 
they  become  heated  too  early  or  too  highly,  they  are  cooled 
by  dabbing  with  wet  rags,  or  by  scattering  hardening 
powder  upon  them. 

For  the  purpose  of  hardening,  the  punch  is  plunged 
vertically  in  the  hardening  water  so  that  the  thick  portion 
is  also  cooled  to  a  depth  of  from  1.18  to  1.57  inches,  the 
punch  being  moved  about  until  cooled  off.  It  is  then 
withdrawn  and  allowed  to  blue  from  the  thick  portion. 
The  blue  temper  color  is  chosen,  and  when  the  punch  has 


164  TOOL-STEEL. 

been  somewhat  highly  heated,  hence  has  been  quite  sharply 
hardened,  it  is  twice  blued.  A  fine  smooth  file  should  just 
take  hold  on  the  tempered  surface.  If  not  cooled  at  all,  or 
only  in  water,  such  punches  become  quite  hot  when  used, 
and  become  covered  with  a  firmly  adhering  layer  of  the 
metal  which  is  punched.  Hence  cooling  is  effected  by 
means  of  oil. 

Before  use  the  punches  are  heated  throughout  in  a  quiet 
coal  fire  so  that  they  can  just  be  touched  with  the  hand, 
or,  what  is  still  better,  they  are  placed  for  some  time  in 
hot,  or  for  a  shorter  time  in  boiling,  water. 

26.  MANDRILS 
for  drawing  metal  cases  and  tubes. 

Quality  of  steel :  Tough  hard  to  tough. 

Hardening :  Uniform  heating  is  readily  attained  only  in 
the  muffle.  Hardening  from  melted  salts  is  especially 
recommended  (see  p.  98). 

Hardening  is  effected  by  plunging  the  mandril  vertically 
in  water,  to  which  a  quantity  of  common  salt  may  advan- 
tageously be  added. 

Tempering  is  effected  by  heating  the  head  of  the  tool  in 
a  gas  flame,  alcohol  flame,  or  by  immersion  in  hot  lead. 

27.  DRAW  PLATES. 

Quality  of  steel :  Hard. 

Hardening :  For  hardening  the  plates  are  heated  in  their 
entirety,  and  the  inner  surfaces,  which  are  engaged  in  use, 
are  protected  from  decarbonizatiori  by  the  use  of  hardening 
paste  and  hardening  powder. 

Narrow  draw  plates  are  hardened  in  their  entirety  by 


APPENDIX.  165 

cooling  off  in  water ;  broad  draw  plates  with  narrow  holes, 
by  conducting  a  powerful  water  jet  through  the  interior. 

28.  PILLOW-BLOCKS  AND  PIVOTS. 

Quality  of  steel :  Medium  hard  to  hard. 

Hardening:  When  large,  the  engaged  surfaces  of  pivots 
are  hardened  under  a  falling  water  jet,  and  tempered  to  the 
pale  yellow  to  straw-yellow  temper  color. 

Pillow-blocks  are  hardened  in  their  entirety  by  cooling 
them,  apertures  down,  in  a  powerful  ascending  water  jet. 
If  the  apertures  are  deep,  cooling  is  effected  under  a  power- 
ful falling  water  jet.  Subsequent  letting  down  is  effected 
over  a  faintly  glowing  charcoal  fire,  in  hot  sand  or  upon  a 
red-hot  iron  plate. 

29.  STONE-WORKING  TOOLS. 

The  selection  of  the  quality  of  steel  for  these  tools  de- 
pends not  only  on  the  kind  of  tool  but  also  on  the  hardness 
of  the  stone  to  be  worked. 

There  is  a  large  variety  of  these  tools,  but  their  construc- 
tion is,  as  a  rule,  very  simple,  and  the  operations  in  hard- 
ening and  tempering  are  readily  carried  out  and  require 
but  little  attention. 

Since  nearly  all  stone-working  tools  are  subject  to  blow 
and  shock  and  are  seldom  hardened  in  their  entirety,  the 
directions  given  for  hardening  hand  chisels,  hot  and  cold 
chisels,  and  hammers  also  apply  to  them. 

When  hard  steel  is  used,  the  treatment  must  of  course  be 
very  careful  and  overheating  be  avoided. 

30.  TOOLS  FOR  THE  MANUFACTURE  OF  NAILS. 
Tools  serving  for  the  manufacture  of  nails  are  subject  to 


166  TOOL-STEEL. 

various  demands  which  have  to  be  satisfied  by  selecting 
the  suitable  quality  of  steel  and  using  an  appropriate 
method  of  hardening. 

The  appliances  for  the  operations  of  hardening  and  tem- 
pering should  be  selected  with  the  greatest  care,  since  the 
efficiency  of  the  machine  is  dependent  on  the  quality  of  the 
tool  used  and  uniformly  good  efficiency  can  only  be  at- 
tained by  uniformly  good  hardening. 

The  varied  demands  made  on  these  tools  and  the  differ- 
ent purposes  for  which  they  are  used,  do  not  allow  of  de- 
tailed directions  to  be  given  for  hardening  them,  and  the 
reader  is  therefore  referred  to  the  hardening  methods  and 
the  appliances  required,  which  have  previously  been  de- 
scribed. 

31.  BALLS. 

Quality  of  steel :  Medium  hard  to  hard. 

Hardening:  In  hardening  balls  which  chiefly  serve  for 
bearings  in  rapid-running  machines,  it  should  be  borne  in 
mind  that  they  must  possess  surfaces  as  pure  and  glass- 
hard  as  possible. 

Small  balls  are  heated,  in  large  numbers  at  one  time,  in 
the  muffle  and  allowed  to  drop  into  a  deep  vessel  filled  with 
water.  Hardening  is  thus  readily  and  completely  effected 
without  fear  of  the  balls  cracking. 

On  the  other  hand,  in  hardening  large  balls  many  diffi- 
culties are  encountered  as  regards  cooling  off  and  cracking, 
since  the  strains  operating  from  all  sides  towards  one  point 
ma}7  not  only  cause  lamellar  peeling  off  of  the  hard  sur- 
faces, but  also  cracking  from  the  interior. 

Since  large  balls  when  simply  plunged  in  the  hardening 
fluid  do  not  lose,  in  sinking  down  in  it,  their  heat  with 


APPENDIX. 


167 


sufficient  rapidity  and  acquire  an  uneven  degree  of  hard- 
ness in  contact  with  the  walls  of  the  vessel,  it,  is  necessary, 
during  cooling,  to  keep  the  hardening  fluid  in  motion. 

By  handling  the  ball  with  ordinary  tongs  the  surface  of 
the  ball  would  readily  receive  impressions  and  the  places 
caught  by  the  tongs  acquire  an  uneven  degree  of  hardness. 

FIG.  66. 


Hence  tongs  are  used,  the  jaws  of  which  are  made  of  very 
thin  iron  in  the  shape  of  a  basket,  Fig.  66,  by  means  of 
which  the  heated  ball  can  be  handled  without  pressure  and 
in  hardening  be  brought  on  all  sides  in  contact  with  the 
cooling  fluid. 

FIG.  67. 


Uniform  cooling  may  also  be  effected  by  means  of  the 
device  shown  in  Fig.  67. 

Fit  a  vessel,  about  3.9  inches  above  the  actual  bottom, 
with  a  sieve-bottom  of  the  shape  shown  in  the  illustration. 
Four  or  more  pipes  conveying  in  a  slanting  direction  water 


1 68  TOOL-STEEL. 

under  great  pressure,  enter  the  vessel  0.39  to  0.78  inch 
above  the  sieve-bottom.  The  upper  edge  of  the  hardening 
vessel  is  provided  with  a  notch  to  allow  the  water  to  run 
off;  and  the  water  supply  is  so  arranged  that  it  can  be 
shut  off.  Before  commencing  hardening  the  supply  pipe  is 
opened  and  the  ball  is  thrown  into  the  strongly  agitated 
water,  in  which  it  sinks  to  the  bottom  and  is  kept  in  con- 
stant motion  by  the  water  flowing  in. 

If  the  hardened  balls  were  allowed  completely  to  cool  off 
in  the  hardening  bath,  much  waste  would  result  from 
cracking.  Therefore,  to  equalize  the  temperature  and 
hardening  strains,  they  are  brought  before  they  are  entirely 
cooled  inside  into  hot  sand,  an  open  fire,  or  hot  water.  It 
is  absolutely  necessary  for  forged  balls  (in  contradistinction 
to  balls  turned  from  the  solid  steel)  to  be  annealed  previous 
to  hardening  in  order  to  remove  the  forging  strains  which 
are  formed  by  upsetting  the  corners  and  edges  of  the  ball- 
form  obtained  from  a  cylinder  or  cube.  Annealing  is 
effected  by  one  of  the  methods  described  on  p.  48. 

32.  ROLLS. 

Rolls  have  to  be  made  of  very  hard  steel,  since  their  sur- 
faces must  possess  a  uniform  glass  hardness,  and  hardening 
them  is  one  of  the  most  difficult  problems  confronting  the 
hardener. 

The  process  of  hardening  a  large  roll  is  described  by  the 
following  example : 

The  danger  of  cracking  from  the  interior  has  been  re- 
duced in  the  construction  of  the  roll  by  boring  it  out.  The 
entire  surface  of  the  roll,  a-a,  b-b,  Fig.  68,  is  to  be  hard, 
while  the  journals,  z-z,  are  to  remain  as  soft  and  tough  as 
possible. 


APPENDIX. 


169 


Previous  to  heating,  the  journals,  z—z,  are  given  a  coat  of 
loam  or  clay,  which,  to  make  it  more  binding,  is  mixed 
with  cows'  hair  and,  to  prevent  peeling  off'  in  consequence 
of  shrinkage  by  heating,  with  chamotte,  graphite,  pulver- 
ized fire-brick,  etc.  Each  journal  is  enclosed  in  a  sheet-iron 
pipe  of  as  large  a  diameter  as  the  thickest  part  of  the  roll, 
and  the  mixture  rammed  in  between  the  pipe  and  the 
journal.  At  m—m  discs  of  sheet-iron  projecting  beyond  the 
edge  of  the  roll  are  arranged.  Finally  the  bore,  the  ends 

FIG.  68. 


of  which  are  provided  with  screw  threads,  are  up  to  the 
latter  rammed  full  of  dry  loam. 

In  heating  the  roll,  which  frequently  requires  several 
hours,  it  must  be  borne  in  mind  that  during  this  time  the 
surface  is  exposed  to  the  injurious  effect  of  the  gases  of 
combustion,  as  well  as  to  decarbonization,  if  suitable  pro- 
tection is  not  provided.  For  this  purpose  the  roll  is 
enclosed  in  a  sheet-iron  pipe  of  somewhat  larger  diameter, 
and  after  the  space  between  the  roll  and  the  pipe  has  been 
rammed  full  of  hoof  shavings  or  soot  the  edges  of  the  pipe 
are  turned  in. 

The  roll  may  now  be  brought  into  the  least  heated  part 
of  a  reverberatory  furnace  of  sufficient  width  and  allowed 
slowly  to  heat.  Heating  in  a  reverberatory  furnace  is  pre- 


170 


TOOL-STEEL. 


ferable,  because  other  appliances,  for  instance,  heating  with 
charcoal,  are  not  always  available,  if  the  roll  has  to  be  turned 
to  attain  a  uniform  temperature.  The  reverberatory  fur- 
nace used  should  have  as  long  a  hearth  as  possible,  so  as  to> 
cause  a  heat  gradually  increasing  towards  the  fire-place. 

FIG.  69. 


The  roll  is  now  gradually  rolled  into  the  higher  heat 
and  turned,  the  more  frequently  the  hotter  it  becomes. 
When  the  roll  is  supposed  to  have  acquired  the  suitable 
hardening  temperature,  a  hook  is  screwed  in  the  threads  on 
the  end  of  the  journal  and  the  roll  is  suspended  by  it  by 
means  of  a  chain.  It  is  then"  freed  from  the  sheet  iron 
discs  which  can  be  readily  removed,  and  quickly  cleansed 
from  adhering  hoof  shavings  with  a  wire  brush.  The  roll 


APPENDIX.  171 

is  then  plunged  in  the  hardening  bath,  which  should  be 
located  near  the  furnace. 

Since  uniform  cooling  off  of  a  roll  of  large  diameter  by 
moving  it  about  in  water  is  impossible,  it  is  allowed  to  rest 
whilst  the  water  is  brought  into  vigorous  motion. 

This  .object  is  attained  by  the  appliance  shown  in  Fig, 
69.  It  consists  of  a  vessel  of  sufficient  depth  and  of  a 
diameter  twice  to  four  times  as  large  as  that  of  the  roll, 
and  is  provided  with  pipe  conduits  for  the  introduction  in 
a  slanting  direction  of  water  under  pressure. 

The  mouths  of  the  pipes  are  made  broad  and  slit-shaped, 
and  a  number  of  them  are  distributed  at  various  heights  so 
that  the  water  around  the  roll  is  set  in  a  vigorously  whirl- 
ing motion.  The  manner  of  using  this  appliance  will  be 
readily  understood  from  Fig.  69. 

The  roll  is  for  several  hours  cooled  with  the  water  Row- 
ing in,  and  then  for  some  time  in  quiet  water. 


172  TOOL-STEEL. 

TABLE  FOR  THE  CONVERSION  OF  CENTIMETERS  TO  INCHES. 


Centi- 

British 

Centi- 

British 

Centi-  i  British 

Centi-   British 

meters. 

Inches. 

meters. 

Inches. 

meters.  Inches. 

meters.   Inches. 

1 

0.394 

51 

20.079 

101 

39.764 

151     59.450 

2 

0.787 

52 

20.473 

102 

40.158 

152    59.844 

3 

1.181 

53 

20.866 

10.< 

40.552 

153    60.237 

4 

1.575 

54 

21.260 

104  i  40.946 

154    60.631 

5 

1.968 

55 

21.654 

105 

41.339 

155    61.025 

6 

2.362 

56 

22.048 

106 

41.733 

156 

61.418 

7 

2.756 

57 

22.441 

107 

42.127 

157 

61.812 

8 

3.150 

58 

22.835 

108 

42.520 

158    62.206 

9 

3.543 

59 

23.229 

109 

42914 

159    62.600 

10 

3.937 

60 

23.622 

110 

43.307 

160    62.993 

11 

4.331 

61 

24.016 

111 

43.702 

161 

63.387 

12 

4.724 

62 

24.410 

112 

44.095 

162 

63781 

13 

5.118 

63 

24.804 

113 

44.489 

163 

64.174 

14 

5.512 

64 

25.197 

114 

44883 

164 

64.568 

15 

5.906 

65 

25.591 

115 

45.276 

165 

64.962 

16 

6.299 

66 

25.985 

116 

45.670 

166 

65.355 

17 

6.693 

67 

26.378 

117 

46.064 

167 

65.749 

18 

7.087 

68 

26.772 

118 

46.457 

168 

66.143 

19 

7.480 

69 

27.166 

119 

46.851 

169 

66.537 

20 

7.874 

70 

27.599 

120 

47.245 

170 

66.930 

21 

8.268 

71 

27.953 

121 

47.639 

171 

67.324 

22 

8.662 

72 

28.347 

122 

48.032 

172 

67.718 

23 

9.055 

73 

28.741 

123 

48.426 

173 

68.111 

24 

9.449 

74 

29.134 

124 

48.820 

174 

68.505 

25 

9.843 

75 

29.528 

125 

49.213 

175 

68.899 

26 

10.236 

76 

29.922 

126 

49.607 

176 

69.293 

27 

10.630 

77 

30.315 

127 

50.001 

177 

69.686 

28 

11.024 

78 

30.709 

128 

50.395 

178 

70.080 

29 

11.417 

79 

31.103 

129 

50.788 

179 

70.474 

30 

11.811 

80 

31.497 

130 

51.182 

180 

70.867 

31 

12.205 

81 

31.890 

131 

51.576 

181 

71.261 

32 

12.51)9 

82 

32.284 

132 

51.969 

182 

71.655 

33 

12.992 

83 

32.678 

133 

52.363 

183 

72.048 

34 

13.386 

84 

33.071 

134 

52.757 

184 

72.442 

35 

13.780 

85 

33.465 

135 

53  151 

185 

72.836 

36 

14.173 

86 

33.859 

136 

53.544 

186 

73.230 

37 

14.567 

87 

34.252 

137   53.938 

187 

73.623 

38 

14.961 

88 

34.646 

138 

54.332 

188 

74.017 

39 

15.355 

89 

35040 

139 

54.725 

189 

74411 

40 

15.748 

90 

35.434 

140 

55.119 

190 

74.804 

41 

16.142 

91 

35.827 

141 

55.513 

191 

75.198 

42 

16.536 

92 

36.221 

142 

55.906 

192 

75592 

43 

16.929 

93 

36.615 

143 

56.300 

193 

75.986 

44 

17.3.3 

94 

37.008 

144 

56.694 

194 

76.379 

45 

17.717 

95 

37.402 

145 

57.088 

195 

76.773 

46 

18.110 

96 

37.796 

146 

57.481 

196 

77.167 

47 

18.504 

97 

38.190 

147 

57.875 

197 

77.560 

48 

18.898 

98 

38.583 

148 

58.269 

198 

77.954 

49 

19.292 

99 

38.977 

149 

58.662 

199 

78.348 

50 

19.685 

100 

39.371 

150 

59.056 

200 

78742 

INDEX. 


ACIDS,  99,  100 
Alcohol,  effect  of,  on  water,  100 
Aluminium  steel,  1 
Animal  substances  for  case-hardening, 

121 
Annealing  boxes,  50 

furnace  for  forged  pieces,  50-52 

long  articles,  55 
general  rule  applying  to,  49 
operation,  controlling   the   result 

of  the,  54,  55 
pots,  furnace  with,  53 
practical  execution  of,  50 
protection  of  steel  from  the  air  in, 

49,  50 
steel,  appliances  for,  48-55 

in  annealing  pots  or  in  anneal- 
ing boxes,  furnace  for,  52 
Anvil,  straightening,  118 
Armor-plates,  mode  of  giving  a  hard 

surface  to,  127 
Arsenic,  4 
Atlas  steel,  1 

BALLS,   hardening   and   tempering 
of,  166-168 
Bearings,    balls    for,    hardening    and 

tempering  of,  166-168 
Bessemer  steel,  1 
Bicycles,  parts  of,  annealing  furnace 

for,  50-52 
Bismarckhuette,  classification  of  steel 

in,  12 

experiments    regarding    the   effi- 
ciency of  tools  at,  136,  137 
investigations  in,  5 
Blast,  action  of,  upon  steel,  31,  32 
for  open  fires,  27 
weakening  the  effect  of,  32 
Blisters,  18 
Boreas  steel,  1,  12 
Bristol-board,  knives  for  stamping  out, 

hardening  and  tempering  of,  159 
Broach   of  large   cross-section,   bored 

out,  79 

Broaches,  hardening  of,  148 
Burning  in,  122,  123 


CANNON  drills,  hardening  and  tem- 
pering of,  149 
Carbide,  4 
Carbon,  effect  of  absorption  of,  by  ironr 

119 
heating  with,  on  iron 

or  steel,  119 
graphitic,  4 
hardening,  3,  4 
occurrence  of,  in  iron,  3,  4 
Carbu retted  hydrogen,  127 
Case-hardening      and      preventatives 
against  superficial  decarboniza- 
tion  and  overheating,  119-127 
application  of,  in  practice,  120 
carbonaceous  substances  employed 

in,  120,  121 
operation  of,  120 
Cast  steel,  2 
Centimeters   to  inches,  table  for  the 

conversion  of,  172 
Centrebits,     forging,    hardening    and 

tempering  of,  144,  145 
Charcoal  for  case-hardening,  121 
furnace  to  be  operated  with,  38 
muffle  furnace  for,  42,  43 
Chisel  steel,  1 
Chisels,  hand,  forging,  hardening  and 

tempering  of,  143,  144 
hot  and  cold,  forging,  hardening 

and  tempering  of,  144 
rivet,  forging,  hardening  and  tem- 
pering of,  144 
Chrome  steel,  1 
Chromium,  7,  8 

Circular  knives,  hardening  and  tem- 
pering of,  160 
Clay,  cooling  with,  104 
Coal,  furnace  for,  40,  41 

smith  or  forge,  25,  26 
Coke-dust,  26 

furnace  to  be  operated  with,  35-38 
hard,  24,  25 

furnace  for,  40,  41 
mild,  soft,  30 
Common  salt,  99 
Cooling  agents,  gaseous,  104 


(173) 


174 


INDEX. 


Cooling  agents,  solid  bodies  as,   104, 

105 

balls,  device  for,  167,  168 
increase  in  the  efficiency  of  tools 

by  a  suitable  process  of,  137 
powder,  125 
rolls,  appliance  for,  171 
tools,  general  rule  for,  83 

in  hardening  and  devices  for 

this  purpose,  83-96 
Copper,  4 

Cracking  from  the  interior,  73,  74 
on  or  near  the  surface,  74,  75 
prevention  of,  70 
Cracks,  16 

force  of  strain  in  forming,  70 
formed  by  uneven  cooling,  85 
progression  of,  107 
Crucible,  cast  iron,  for  melting  metals 

or  salts,  68 
steel,  silicon  in,  5 
steel,  1,  2 

Cutters,  annealing  furnace  for,  50-52 
broad,  protecting  the  sharp  cor- 
ners of,  81,  82 
hardening  and  tempering  of,  149- 

152 

Cutting   knives  for  wood,  hardening 
and  tempering  of,  159 

DEFECTS    of   hardened   tools,    in- 
vestigation of,  131-139 
Diamond  Hteel,  1 

Dies    and    punches,    for     perforating  ! 
holes  in  metals,  hard-  I 
ening   and   tempering  i 
of,  162-164 
harden  ing  and  tempering 

of,  160-162 

jstamps,  hardening  and   tem- 
pering of,  162 
Draw-plates,  hardening  of,  65,  66 

and    tempering    of, 

164,  165 

Drills,    cannon,    hardening  and  tem- 
pering of,  149 

spiral,  for  metal,  hardening  and 
tempering  of,  148,  149 


Fire,  open,  protection  of  steel  from  the 

blast  in  an,  32 
tempering  in  an,  112 
zones  of  heat  in  an,  27 
-treatment  of  steel,  practice  of  the, 

22-48 
Flaws,  18 
Forge  coal,  25,  26 
Forging,  changes  in  shape  by,  20 

reverberatory   furnace,    ordinary, 

44,  45 
strains,  -^9 

Fracture,  manner  of  effecting,  21 
of  steel,  appearance  of,  17-19 
Fuel,  charcoal  as,  30,  31 
Furnace,  annealing,  for  forged  pieces, 

50-52 

long  articles,  55 
for  coal,  40,  41 

hard  coke,  24,  25,  40,  41 
annealing  steel  in  an  annealing 
pot  or  in  annealing  boxes,  52 
heating  long  articles,  39,  40 
tempering   by   means  of    hot 

sand,  113 

forging  and  hardening  reverbera- 
tory, 46 

most  simple  type  of,  35 
ordinary    forging    reverberatory, 

44,  45 
provisional,  conversion  of  an  open 

fire  into  a,  28,  29 
reverberatory,  small,  45 

with  Gasteiger's  patented  fire- 
place, 47,  48 
muffle,  48 
small     reverberatory,    with    step 

grate,  47 
to  be  operated  with  charcoal,  38 

coke,  35-38 

with  annealing  pots,  53 
two  muffles,  41,  42 
Furnaces,  muffle,  40-44 


EDGE  cracks,  17 
Emery  wheels,  cracks  caused  by, 
137,  138 

FILES,  annealing  furnace  for,  50-52 
protection  of  teeth  of,  in  harden- 
ing, 124,  125 

Fire,  open,  conversion  of  an,  into  a 
provisional  furnace,  28,  29 


GAS,  case-hardening  steel  with,  127 
flame,  tempering  by  means  of  a, 

112 

muffle  furnace  for,  43 
Gaseous  cooling  agents,  104 
Gasteiger's  patented  fireplace,  47,  48 
Graphite,  4 
Graphitic  carbon,  4 

HAMMER,  straightening,  118 
swages,    hardening  and    tem- 
pering of,  154-156 

Hammers,  hardening  and  tempering, 
of,  153,  154 


INDEX. 


175 


Hand  chisels,  forging,  hardening  and 

tempering  of,  143,  144 
hammers,  hardening  and  temper-  i 

ing  of,  153,  154 
Hard-centred  steel,  1 
Hard  coke,  24,  25 

Hardened   tools,  investigation  of  de- 
fects of,  131-139 

Hardening,  avoidance  of  failure  in,  73 
bath,  formation  of  steam  in  the, 

83,  84 

by  means  of  a  jet,  95 
by  pressure,  104 
carbon,  3,  4 
changes  in  steel  in,  62 
cause  of  changes  in  steel  in,  63,  64 
cooling  of  tools  in,  and  devices  for 

this  purpose,  83-96 
covering  portions  of  the  tools  in, 

87,88 

definition  of,  62 
gradual  progress  of,  82,  83 
of  tools  which  are  to  be  hardened 

in  their  entirety,  73-79 
which  are  only  to  be  par- 
tially hardened,  80-83 
of  tool-steel  in  general,  62—73 
paste,  123 
property  of  steel  of  assuming  fixed 

dimensions  in,  65,  66 
powder,  123,  124 
steel,  appliances  for,  55-61 
water  mixed  with  insoluble  con- 
stituents, ]  00, 
101 

oils  or  fats,  101 
soluble  constitu- 
ents, 98-1 00 
most  suitable  temperature  of, 

97 

used  for  some  time,  value  of,  98 
Heating  appliances  for  steel,  23 
choice  of  fuel  for,  23,  24 
long  thin  articles,  appliance  for, 

27-29 
steel  in  an  open  fire,  drawbacks 

of,  34 

tools  from  the  outside,  75.  76 
Heels,  knives  for  stamping  out,  hard- 
ening and  tempering  of,  159 
Hot  and  cold  chisels,  forging,  harden- 
ing and  tempering  of,  144 

TNCHES,  table  for  the  conversion 
-L     of  centimeters  to,  172 
Ingot  steel,  1 

Investigation  of  defects  of  hardened 
tools,  131-139 


Iron,    effect     of    hardening    on    the 

strength  of,  140 
heating    with    carbon 

on,  119 

occurrence  of  carbon  in,  3,  4 
red  hot,  use  of,  for  tempering,  112 
works,  products  of,  employed  in 
the  manufacture  of  tools,  1 

KNIFE  steel,  1 
Knives,  circular,  hardening  and 

tempering  of,  160 
for  splitting  leather,  harden- 
ing and  tempering  of,  159 
long,  furnace  for  tempering, 

114,  115 

stamping,      hardening     and 
tempering  of,  159 

LEAD,    mass  for  preventing,   from 
adhering  to  tools,  59 
molten,     disadvantages     of 
heating  steel    in, 
58,  59 
partial  tempering  in, 

114 

use  of,  for  hardening.  103 
Leather,  knives  for  splitting,  harden- 
ing and  temper- 
ing of,  159 
stamping      out, 
hardening    and 
tempering    of, 
159 

Light,  influence  of,  in  judging  the  de- 
gree of  temperature,  33   34 
Lime,  addition  of,  to  hardening  water. 

100 

Liquids  used  in  quenching  steel,  97- 
105 

1ITACHINE  knives  for  cutting  paper, 
1*-L  hardening  and  tempering  of,  159 
Magnet  steel,  1,  14 

Mandrils  for  drawing  metal  cases  and 
tubes,  hardening  and  tempering  of, 
164 
Manganese,  6 

influence  of,  upon  the  change  in 

volume  of  steel,  72 
steel,  actual,  6 
Martin  steel,  1 
Mercury,  use  of,  for  hardening,  102, 

103 
Metal,  hardening  and  tempering  spiral 

drills  for,  148,  149 

Metals,  cast-iron  crucible  for  melting, 
68 


176 


INDEX. 


Metals,   molten,  cooling  wood-cutters 

in,  152 

tempering  in,  110 
punches  and  dies  for  perforating 
holes  in,  hardening  and   tem- 
pering of,  1(52-164 
use  of,  for  hardening,  102,  103 
Mild-centred  steel,  1,  15 
Milling  tools,  hardening  and  temper- 
ing of,  153 
Molybdenum,  8,  9 

steel,  9 
Muffle  furnace  for  charcoal,  42,  43 

gas,  43 

in  an  open  fire,  29,  30 
Muffles,  paste  for  repairing  cracks  in, 

43 
Mushet  steel,  12 

"VTAILS,  tools  for  the  manufacture  of, 
I*      hardening  and  tempering  of,  165, 

166 

Natural  steel,  1,  12 
Nickel,  8 

steel,  1,  8 

AIL,  blazing  off'  with,  110 

v/        tempering  tools  in,  111,  112 

Oils  and  fats,  102 

hardening   water  mixed 

with,  101 

Open  fire,  conversion  of  an,  into  a  pro- 
visional furnace,  28,  29 
muffle  built  in  an,  29,  30 
protection  of  steel  from  the 

blast  in  an,  32 
tempering  in  an,  112 
zones  of  heat  in  an,  27 

PAPER,  knives  for  stamping  out, 
hardening  and  tempering  of, 
159 

machine     knives    for    cutting, 
hardening  and  tempering  of, 
159 
Pasteboard,  knives  for  stamping  out, 

hardening  and  tempering  of,  159 
Phosphorus,  4 
Pillow-blocks  and   pivots,    hardening 

and  tempering  of,  165 
Pipe-cutters,  hardening  and  tempering 

of,  152 
Pipe-cutting    knives,    hardening   and 

tempering  of,  153 

Planing  knives  for  wood,  hardening 

and  tempering  of,  159 

forging    and    hardening 

of,  145 
Potash,  addition  of,  to  water,  98 


Potash,  yellow  prussiate  of,  60 
:  Potassium  chromate,  59,  60 
Powder  for  cooling,  81,  82 
!  Puddled  steel,  I 
|  Punch  steel,  1 

heating  a,  81 

j  Punches  and  dies  for  perforating  holes 
in  metals,  hardening 
and  tempering  of, 
162-164 

hardening  and  temper- 
ing of,  160-162 

^DEGENERATION   of  steel  which 
JLV     has  been  spoiled  in  the  fire,  129- 

131 
Reverbemtory    furnace,    forging    and 

hardening,  46 
small,  45 

with  step  grate, 

47 
ordinary  forging,  44, 

45 

with  Gasteiger' s  pat- 
ented fireplace, 
47,  48 

with  muffle,  48 
Rivet  chisels,  forging,  hardening  and 

tempering  of,  144 
Riveting    hammers,    hardening    and 

tempering  of,  153,  154 
Roll  shear-knives,  hardening  and  tem- 
pering of,  156 

turning  knives,  forging  and  hard- 
ening of,  146 

Rolling,  changes  in  shape  by,  20 
Rolls,   hardening  and   tempering  of, 
168-171 

SAL  ammoniac,  99 
Salt,  common,  59,  99 
mode  of  fusing,  60 

Salts,  cast-iron  crucible  for  melting,  68 
fused,  heating  steel  in,  59-61 
mixture  of,  59 
Sand,  cooling  with,  104 
hot,  heating  in,  76 

tempering  by  means  of,  113 
Saws,  furnace  for  heating,  39,  40 
Scales,  16 
Screw-dies,  hardening  and  tempering 

of,  147,  148 
taps,  hardening  and  tempering  of, 

146,  147 
•Scythe  steel,  1 
Seams,  16,  17 
Self-hardened  steel,  1,  12 
Shear  steel,  1 


INDEX. 


177 


Shear  knives,  furnace  for  heating,  39,  40 
hardening  and  tempering  of, 

156-159 

long,  heating  of,  157,  158 
round   and   circular,   harden- 
ing and  tempering  of,  156 
Silicon  in  crucible  cast  steel,  5 
Sledge  hammers,  hardening  and  tem- 
pering of,  153,  154 
Smith  coal,  25,  26 
Soap  water,  effect  of,  100 
Soda,  addition  of,  to  water,  98,  99 

carbonate  of,  59 
Soft  centred  steel,  1,  15 
Soles,  knives  for  stamping  out,  hard- 
ening and  tempering  of,  159 
Solid  bodies  as  cooling  agents,  104, 105 
Special  steel,  labels  on,  10 
Special  steels,  12-15 
Spindle,  manner  of  packing  a,  for  case- 
hardening,  121,  122 
Spiral  drills  for  metal,  hardening  and 

tempering  of,  148,  149 
Springs,  hardening  of,  103 

tempering  of,  110 

Stamping  knives,  hardening  and  tem- 
pering of,  1 59 

Stamps  and  dies,  hardening  and  tem- 
pering of,  162 
Steam,  formation  of,  in  the  hardening 

bath,  83,  84 

Steel,  accidental  admixtures  in,  4,  5 
action  of  blast  upon,  31,  32 
adaptation  of  appliances  for  heat- 
ing of,  23 

appearance  of  fracture  of,  17-19 
appliances  for  annealing,  48-55 

hardening,  55-61 
baked,  130 
blisters  on    the   surfaces  of   the 

fractures  of,  18 
burnt,  129 
carrier  of  the  hardening  capacity 

in,  3,  4 
case-hardening  of,  by  cementation, 

127 

causes  of  changes  in,  in  harden- 
ing, 63,  64 
changes  in  dimensions  of,  64,  65 

in  hardening,  62 
cracking  of,  68,  69 
cracks  on  surface  of,  16 
crucible  cast,  silicon  in,  5 
dead,  130,  131 
decrease  in  volume  of,  65 
defects  of,  which  may  be  observed 
on  the  surfaces  of  the 
fractures  of,  18,  19 

12 


Steel,  defects  of,  which  may  show  on 

the  surface  of,  16,  17 
definition  of,  3 
designations  of,  1,2 
disadvantages     of     heating,     in 

melted  lead,  58,  59 
drawbacks  of  heating,  in  an  open 

fire,  34 

edge  cracks  on  surface  of.  17 
effect  of  chromium  upon  the  prop- 
erties of,  7,  8 
hardening  on  the  strength 

of,  140 
heating  with   carbon  on, 

119 

nickel  upon  the  proper- 
ties of,  8 

tempering  on  the  strength 
and  toughness  of,  140, 
141 

tungsten   upon  the  prop- 
erties of,  7 
fire  treatment  of,  practice  of  the, 

22-48 
flaws  in  the  centre  of,  18,  19 

on  the  surfaces  of  the  frac- 
tures of,  18 

furnace  for  annealing,  in  anneal- 
ing pots  or  annealing  boxes, 
52 

hardened  and  unhardened,  tables 
showing  the  influence  of 
the  various  degrees  of  tem- 
perature upon,  and  their 
general  application  in  prac- 
tice, 21,  22 

conditions  on  which  the  ap- 
pearance of  the  fracture  of, 
depends,  21,  22 
increase  in  volume  of,  67 
observations  on  the  fracture 

of,  69 
tempering  of,  and  devices  for 

this  purpose,  105-116 
heating  appliances  for,  23 

of.  in  fused  salts,  59-61 
hints  for  the   choice  of  suitable 

appliances  for  hardening,  56 
improving      the     properties      of 

strength  of,  140.  141 
influence  of  manganese  upon  the 

change  in  volume  of.  72 
liquids  used  in  quenching,  97-105 
magnet,  1,  14 
mild-centred,  1,  15 
modes  of  straightening,  117 
Mushet,  12 
natural,  1,  12 


178 


INDEX. 


Steel,  observations  on  the  fracture  of,  | 
with  regard  to  the  structure  in  I 
the  hardened  and  non-hardened  i 
state,  19-22 
overheated,  129,  130 
overheating  of,  in  welding,  127 
property   of,   of    assuming    fixed 
dimensions  in  hardening,  65,  66 
protection  of,  from  the  air  in  an- 

nealing, 49,  50 
from   the  blast   in  an 

open  fire,  32 
roasted,  130 

rolled  or  forged,  properties  of,  140 
scales  on  surfaces  of,  16 
seams  on  surface  of,  16,  17 
self-hardened,  1,  12 
shaping  of,  22,  23 
soft-centred.  1,  15 
spots  on  the  surfaces  of  the  frac- 

tures of,  18 
strains  in,  65 

unhardened,  conditions  on  which 
the  appearance  of  the  fracture 
of,  depends,  20,  21 
very  hard  special  turning,  12,  13 
welding  of,  127-129 
which  has  been  spoiled  in  the  fire, 

regeneration  of,  129-131 
Steels,  special,  12-15 
Stone-working    tools,    hardening   and 

tempering  of,  165 
Straightening  claw,  117,  118 

tools,  116-119 
Strain,  force  of,  67,  68 

in  forming  cracks,  70 
Strains,  effect  of,  71 
forging,  49 
in  steel,  65 

Structure  of  hardened  steel,  conditions 
on    which    the   appear- 
ance of  the  fracture  of, 
depends,  21,  22 
unhardened   steel,   condi- 
tions on  which  the  ap- 
pearance of  the  fracture 
of,  depends.  20,  21 
Swages,  annealing  furnace  for,  50-52 
hammer,  hardening  and  temper- 
ing of,  154-156 


for  the  conversion  of  centi- 

J-     meters  to  inches,  172 

Tables  showing  the  influence  of  the  j 
various  degrees  of  temperature  upon  j 
hardened  and  unhardened  steel,  and  • 
their  general  application  in  prac-  1 
tice,  21,  22 


Temper  color,  definition  of,  62 

uneven    appearance    of, 

109 

Temper  colors,  recognition  of  the  ad- 
vance of  the  heat  by 
the,  106 

requirements  for  the  ap- 
pearance of,  63 
Temperature,    influence    of    light,   in 

judging  the  degree  of,  33,  34 
Tempering  by  means  of  hot  sand,  113 
effect    of,    on    the    strength   and 

toughness  of  steel,  140,  141 
from  the  interior,  105-108 

assistance  in, 
by  heating 
from  the  out- 
side, 108 

in  oil,  device  for,  111,  112 
long  knives,  furnace  for,  114,  115 
modes  of  effecting,  105 
of  hardened  steel  and  devices  for 

this  purpose,  105-116 
Tin,  use  of,  for  hardening,  103         ' 
Titanium,  8,  9 
steel,  2,  9 
Tongs  for  handling  balls,  167 

formation  of  cracks  caused  by,  85, 

86 

shapes  of,  86 
Tool,  imparting  special  toughness  to  a, 

106 
main  points  to  be  considered  in 

the  construction  of  a.  79 
-steel,  classification  of,  according 
to  the  degree  of  hardness 
and  the  purpose  for  which 
it  is  to  be  used,  9-15 
commercial,  observations  on 
the    external    appear- 
ance of,  16-19 
stamps  and  labels  on,  10 
composition  of,  and  its  classi- 
fication   according    to    it, 
3-9 
danger    of    overheating  and 

burning,  11,  12 
designations  of  hardness  of,  10 
experiments     regarding    the 
cutting  power  of,  104,  105 
for  definite  purposes,  14,  15 
general  designation  of,  1 
groups  of,  9,  10 
hardening  of,  in  general,  62- 

73 

intentional  admixtures  in,  5-9 
observations  on  the  fracture 
of,  66 


INDEX. 


179 


Tool-steel,  selection  of,   for  a  deter- 
mined purpose,  11 
standard  for  judging  the  fit- 
ness of  a,  11 
structure  of,  19 

Tools,  avoidance  of  superficial  scale- 
like  separations  on,  75 
boring  out  of,  79 
cause  of  distortion  of,  117 
cooling  of,  in  hardening  and  de- 
vices for  this  purpose,  83-96 
covering  portions  of,  in  harden- 
ing, 87,  88 
cracking  of,  73-75 
cracks  in,  134 
disc-like,  tempering  of,  112 
division  of,  into  sections,  78 
experiments    regarding    the   effi- 
ciency of,  136,  137 
flat,  defects  of,  133 
for  the  manufacture  of  nails,  hard- 
ening and   tempering  of,   165, 
166 

general  rule  for  cooling,  83 
hardened,    immediate    inspection 

of,  136 
increase  in  the  toughness  of, 

by  boiling  water,  110 
investigation    of    defects  of, 

131-139 
uneven  degree  of  hardness  of, 

134 
heating  of,  from  the  outside,  75, 

76 

in  use,  138,  139 
so  that  the  air  is  abso- 
lutely excluded,  57 
hints  for  the  inspection  of,  132- 

135 

hollow,  hardening  of,  95,  96 
large,  tempering  of,  114,  115 
long,  straightening  of,  117 
mass   for  preventing    lead    from 

adhering  to,  59 
milling,  hardening  and  tempering 

of,  153 
of  small  cross  section,  tempering 

of,  108 
partial  tempering  of,  in  hot  sand, 

partially  hardened,  error  in  tem- 
pering, 116 

paste  of  carbonaceous  substances 
for  the  protection  of,  125,  126 

perforated,  tempering  of,  112 

products  of  iron  works  employed 
in  the  manufacture  of,  1 

requisites  in  tempering,  109,  110 


Tools,  roasted  or  baked,  135 

severance  of  corners  and  edges  of, 

132 

small,  cracks  in,  132,  133 
soft  skin  on  the  surface  of,  135 
stone  -  working,     hardening    and 

tempering  of,  165 
straightening  of,  116-119 

by  uneven  heating 
and    cooling, 
118,  119 
tempering  of,  in  molten  metals, 

110 

oil,  111,  112 

thin,  flat,  straightening  of,  117 
to  be  partially  hardened,  groups 

of,  80,  81 

unevenly  heated,  cooling  of,  125 
unequal  cooling  of,  84,  85 
uniform     degree     of    insufficient 

hardness  of,  135 

use  of  water  for  hardening,  89-96 
which   are   only   to   be   partially 
hardened,     hardening 
of,  80-83 

to  be  hardened  in  their 
entirety,  hardening  of, 
73-79 
with  engraved  surfaces,  crumbling 

of,  138 
working    under    especially    high 

pressure,  hardening  of,  77 
Tungsten,  6,  7 

steel,  1 

Turning  knives,  forging  and  harden- 
ing of,  145 

steel,  very  hard  special,  12,  13 
Tuyeres  for  open  fires,  27 


u 


NIVERSAL  steel,  1 


VANADIUM,  8,  9 
steel,  1,  9 

TT7ATER,    ascending,    use    of,    for 

hardening,  93,  94 
falling,  use  of,  for  hardening, 

90-92 

hot,  heating  in,  76 
increase  in  the  heat-conducting 

power  of,  97,  98 
pure,  97,  98 
running,  use  of,  for  hardening, 

89 

Weld  steel,  1,  2 
Weldable  ingot  steel,  2 
Welding  of  steel,  127-129 


180 


INDEX. 


Wood-cutters,   cooling  of,  in   molten    "VTELLOW  prnssiate  of  potash,  60 

inetals,  152 
Wood,    planing    and    cutting    knives 


for,    hardening  and   tempering  of, 
159 


I7INC,  use  of,  for  hardening,,  103 


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BIRD. — Tl?e  American  Practical  Dyers'  Companion: 
Comprising  a  Description  of  the  Principal  Dye-Stuffs  and  Chemicals 
used  in  Dyeing,  their  Natures  and  Uses ;  Mordants,  and  How  Made ; 
with  the  best  American,  English,  French  and  German  processes  for 
Bleaching  and  Dyeing  Silk,  Wool,  Cotton,  Linen,  Flannel,  Felt, 
Dress  Goods,  Mixed  and  Hosiery  Yarns,  Feathers,  Grass,  Felt,  Fur, 
Wool,  and  Straw  Hats,  Jute  Yarn,  Vegetable  Ivory,  Mats,  Skins, 
Furs,  Leather,  etc.,  etc.  By  Wood,  Aniline,  and  other  Processes, 
together  with  Remarks  on  Finishing  Agents,  and  Instructions  in  the 
Finishing  of  Fabrics,  Substitutes  for  Indigo,  Water-Proofing  of 
Materials,  Tests  and  Purification  of  Water,  Manufacture  of  Aniline 
and  other  New  Dye  Wares,  Harmonizing  Colors,  etc.,  etc. ;  embrac- 
ing in  'all  over  800  Receipts  for  Colors  and  Shades,  accompanied  b\ 
170  Dyed  Samples  of  Raw  Materials  and  Fabrics.  By  F.  J.  BIRD, 
Practical  Dyer,  Author  of  "The  Dyers'  Hand- Book."  8vo.  1^7.50 

BLINN.— A  Practical  Workshop  Companion  for  Tin,  Sheet- 

Iron,  and  Copper-plate  Workers  : 

Containing  Rules  for  describing  various  kinds  of  Patterns  used  by 
Tin,  Sheet-Iron  and  Copper- plate  Workers;  Practical  Geometry; 
Mensuration  of  Surfaces  and  Solids;  Tables  of  the  Weights  of 
Metals,  Lead-pipe,  etc. ;  Tables  of  Areas  and  Circumference! 
of  Circles ;  Japan,  Varnishes,  Lackers,  Cements,  Compositions,  etc., 
etc.  By  LEROY  J.  BLINN,  Master  Mechanic.  With  One  Hundred 
.and  Seventy  Illustrations.  I2mo.  .  .  .  .  .  $2.50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE 


BOOTH.— Marble  Worker's  Manual: 

Containing  Practical  Information  respecting  Marbles  in  general,  their 
Cutting,  Working  and  Polishing ;  Veneering  of  Marble  ;  Mosaics ; 
Composition  and  Use  of  Artificial  Marble,  Stuccos,  Cements,  Receipts, 
Secrets,  etc.,  etc.  Translated  from  the  French  by  M.  L.  BOOTH. 
With  an  Appendix  concerning  American  Marbles.  I2mo.,  cloth  $1.50 
BOOTH  and  MORFIT.— The  Encyclopaedia  of  Chemistry, 

Practical  and  Theoretical : 

Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine  and  Pharmacy.  By  JAMES  C.  BOOTH,  Melter 
and  Refiner  in  the  United  States  Mint,  Professor  of  Applied  Chem- 
istry in  the  Franklin  Institute,  etc.,  assisted  by  CAMPBELL  MORFIT, 
author  of  "  Chemical  Manipulations,"  etc.  Seventh  Edition.  Com- 
plete in  one  volume,  royal  8vo.,  978  pages,  with  numerous  wood-cuts 
and  other  illustrations (Scarce.) 

BRAMWELL.— The  Wool  Carder's  Vade-Mecum  . 
A  Complete  Manual  of  the  Art  ul   Carding  Textile  Fabrics.     By  W. 
C.  BRAMWELL.     Third  Edition,  revised  and  enlarged.     Illustrated. 

Pp.  400.     I2mo. $2.50 

BRANNT.— A   Practical   Treatise  on  Animal  and  Vegetable 

Fats  and  Oils  : 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chem- 
ical Properties  and   Uses,  the   Manner  of   Extracting  and    Refining 
them,  and  Practical  Rules  tor  Testing  them ;  as  well  as  the  Manufac- 
ture of  Artificial  Butter  and  Lubricants,  etc.,  with  lists  of  American 
Patents  relating  to  the  Extraction,  Rendering,  Refining,  Decomposing, 
and  Bleaching  of  Fats  and  Oils.     By  WILLIAM  T.  BRANNT,  Editor 
of  the  "  Techno-Chemical  Receipt  Book."     Second  Edition,  Revised 
and  in  a  great  part  Rewritten.     Illustrated  by  302  Engravings.     In 
Two  Volumes.     1304  pp.     8vo.      .....         $10.00 

BRANNT.— A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science ; 
comprising  the  Chemistry,  Raw  Materials,  Machine-v.  and  Utensils 
and  Various  Processes  of  Manufacture,  including  a  great  variety  of 
formulas.  Edited  chiefly  from  the  German  of  Dr.  C.  Deite,  A. 
Engelhardt,  Dr.  C.  Schaedler  and  others;  with  additions  and  lists 
of  American  Patents  relating  to  these  subjects.  By  WM.  T.  BRANNT 
Illustrated  by  163  engravings.  677  pages.  8vo.  .  .  $7-S° 

BRANNT.— India  Rubber,  Gutta  Percha  and  Balata : 

Occurrence,  Geographical  Distribution,  and  Cultivation,  Obtaining 
and  Preparing  the  Raw  Materials,  Modes  of  Working  and  Utilizing 
them,  Including  Washing,  Maceration,  Mixing,  Vulcanizing,  Rubber 
and  Gutta- Percha  Compounds,  Utilization  of  Waste,  etc.  By  WiLL- 
IAM  T.  BRANNT.  Illustrated.  I2mo.  (1900.)  .  .  13.00 


HENRV  CAREY  BAIKD  &  CO.'S  CATALOGUE. 


BRANNT— WAHL.—  The  Techno-Chemical  Receipt  Book-. 

Containing  several  thousand  Receipts  covering  the  latest,  mos»  «fD 
jxmant,  and  most  useful  discoveries  in  Chemical  Technology,  ant 
their  Practical  Application  in  the  Arts  and  the  Industries.  Editec 
chiefly  from  the  German  of  Drs.  Winckler,  Eisner,  Heintze,  Mier 
zinski,  Jacobsen,  Koller,  and  Heinzerling,  with  additions  by  WM.  1. 
BRANNT  and  WM.  H.  WAHL,  PH.  D.  Illustrated  by  78  engravings. 
!2nio.  495  pages  .  .  ...  $2.00 

BROWN. — Five  Hundred  and  Seven  Mechanical  Movements: 
Embracing  all  those  which  are  most  important  in  Dynamics,  Hy- 
draulics, Hydrostatics,  Pneumatics,  Steam-Engines,  Mill  and  other 
Gearing,  Presses,  Horology  and  Miscellaneous  Machinery;  and  in- 
cluding many  movements  never  before  published,  and  several  of 
which  have  only  recently  come  into  use.  By  HENRY  T.  BROWN. 
.  I2mo $1.00 

BUCKMASTER.— The  Elements  of  Mechanical  Physics  : 
By  J.  C.   BUCKMASTER.       Illustrated    with    numerous   engravings. 
I2mo $i.oo 

BULLOCK.— The  American  Cottage  Builder  : 
A  Series  of  Designs,  Plans  and  Specifications,  from  $200  to  $20,000, 
for  Homes  for  the  People ;  together  with  Warming,  Ventilation, 
Drainage,  Painting  and  Landscape  Gardening.  By  JOHN  BULLOCK, 
Architect  and  Editor  of  "  The  Rudiments  of  Architecture  and 
Building,"  etc.,  etc.  Illustrated  by  75  engravings.  8vo.  $2.50 

BULLOCK. — The  Rudiments  of  Architecture  and  Building: 
For  the  use  of  Architects,  Builders,   Draughtsmen.   Machinists,  En- 
gineers and  Mechanics.     Edited  by  JOHN  BULLOCK,  author  of  "The 
American  Cottage  Builder."  Illustrated  by  250  Engravings.  8vo.$2.5o 

BURGH. — Practical    Rules    for    the    Proportions   of     Modern 

Engines  and  Boilers  for  Land  and  Marine  Purposes. 
By  N.  P.  BURGH,  Engineer.     I2mo.  ....         $1.50 

BYLES. — Sophisms    of     Free    Trade    and    Popular    Political 

Economy  Examined. 

By  a  BARRISTER  (SiR  JOHN  BARNARD  BYLES,  Judge  of  Common 

Pleas).       From  the    Ninth    English    Edition,  as    published    by    the 

Manchester  Reciprocity  Association.      I2mo.      .         .         .         $1.25 

6OWMAN.— The  Structure  of  the  Wool  Fibre  in  its  Relation 

to  the  Use  of  Wool  for  Technical  Purposes  : 
Being  the  substance,  with  additions,  of  Five  Lectures,  delivered  at 
\he  request  of  the  Council,  to  the  members  of  the  Bradford  Technical. 
College,  and  the  Society  of  Dyers  and  Colorists.     By  F.  H.  Bow 
MAN,  D.  Sc.,   F.  R.  S.  E.,  F.  L.  S.      Illustrated   by  32   engravings. 
8vo $5.00 

BYRNE. — Hand-Book  for  the  Artisan,  Mechanic,  and  Engi- 
neer: 

Comprising  the  Grinding  and  Sharpening  of  Cutting  Tools,  Abra-.ve 
Processes,  Lapidary  Work,  Gem  and  Glass  Engraving,  Varnishing 
and  Lackering,  Apparatus,  Materials  and  Processes  for  Grinding  and 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


Polishing,  etc.  By  OLIVER  BYRNE,  Illustrated  by  185  wood  en- 
gravings. 8vo. $5.00 

BYRNE. — Pocket-Book  for  Railroad  and  Civil  Engineers: 
Containing  New,  Exact  and  Concise  Methods  for  Laying  out  Railroad 
Curves,  Switches,  Frog  Angles  and  Crossings ;  the  Staking  out  of 
work  ;  Levelling  ;  the  Calculation  of  Cuttings  ;  Embankments ;  Earth- 
work, etc.  By  OLIVER  BYRNE.  i8mo.,  full  bound,  pocket-book 
form $1.50 

BYRNE. — The  Practical  Metal- Worker's  Assistant : 
Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all  Metals 
and  Alloys;  Forging  of  Iron  and  Steel;  Hardening  and  Tempering; 
Melting  and  Mixing;  Casting  and  Founding  ;  Works  in  Sheet  Metal; 
the  Processes  Dependent  on  the  Ductility  of  the  Metals;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal- 
workers. With  the  Application  of  the  Art  of  Electro-Metallurgy  to 
Manufacturing  Processes ;  collected  from  Original  Sources,  and  from 
the  works  of  Holtzapffel,  Bergeron,  Leupold,  Plumier,  Napier, 
Scoffern,  Clay,  Fairbairn  and  others.  By  OLIVER  BYRNE.  A  new, 
revised  and  improved  edition,  to  which  is  added  an  Appendix,  con- 
taining The  Manufacture  of  Russian  Sheet-Iron.  By  JOHN  PERCY, 
M.  D.,  F.  R.  S.  The  Manufacture  of  Malleable  Iron  Castings,  and 
Improvements  in  Bessemer  Steel.  By  A.  A.  FESQUET,  Chemist  and 
Engineer.  With  over  Six  Hundred  Engravings,  Illustrating  every 
Branch  of  the  Subject.  8vo $5-°o 

BYRNE.— The  Practical  Model  Calculator: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work,  Naval 
Architect,  Miner  and  Millwright.  By  OLIVER  BYRNE.  8vo.,  nearly 
600  pages £3.00 

CABINET  MAKER'S  ALBUM  OF  FURNITURE  i 
Comprising  a  Collection  of  Designs  for  various  Styles  of  Furniture. 
Illustrated  by  Forty-eight  Large  and  Beautifully  Engraved   Plates. 
Oblong,  8vo $1.50 

CALLINGHAM. — Sign  Writing  and  Glass  Embossing: 

A    Complete  Practical    Illustrated    Manual  of  the   Art.     By  JAMES 

CALLINGHAM.     To  which  are  added  Numerous  Alphabets  and  the 

Art  of  Letter  Painting  Made  Easy.     By  JAMES  C.  BADENOCH.     258 

pages.     I2mo. $1.50 

CAMPIN. — A  Practical  Treatise  on  Mechanical  Engineering: 
Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools,  Work. 
shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam- 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Iron 
Ores.  By  FRANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention ;  with  a  Chapter  on  Explosions.  Bv  R. 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  (Scarce.) 


HENRY  CAREY  BAIRD  &  CG.o  CATALOGUE. 


CAREY. — A  Memoir  of  Henry  C.  Carey. 
By  DR.  WM.  ELDER.    With  a  portrait.     8vo.,  cloth         .         .        75 

CAREY.— The  Works  of  Henry  C.  Carey  : 

Harmony  of  Interests  :    Agricultural,  Manufacturing  and  Commer- 
cial.    8vo.  .....  $1.25 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  i  vol.  I2mo.  .  $2.00 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  #10.00 

Past,  Present  and  Future.     8vo $2.50 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  $7-SQ 
The  Slave-Trade,  Domestic  and  Foreign;  Why  it  Exists,  and 
How  it  may  be  Extinguished  (1853).  8vo.  .  .  .  $2.00 
The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental  and  Moral  Science  (1872).  8vo.  .  .  $2.50 

CLARK. — Tramways,  their  Construction  and  Working : 

Embracing  a  Comprehensive  History  of  the  System.  With  an  ex- 
haustive analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air;  a  description  of  the 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses. By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  I  vol.  8vo.  .  #7.50 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man 
agement.  By  ZERAH  COLBURN.  Illustrated.  i2mo.  .  $1.00 

COLLENS. — The  Eden  of  Labor;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"   "The  Historj 
of  Charity,"  etc.     I2mo.     Paper  cover,  $  I.  oo;  Cloth          .         $1.25 

COOLEY. — A  Complete  Practical  Treatise  on  Perfumery: 
Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Articlei 
With   a  Comprehensive    Collection  of  Formulae.     By   ARNOLD 
COOLEY.    i2mo.        . $1.50 

COOPER. — A  Treatise  on  the  use  of  Belting  for  the  Tram. 

mission  of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar 
ranging  Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten 
ings.  Examples  and  Rules  in  great  number  for  exhibiting  and  cat 
culating  the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Management  o' 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  witn 
chapters  on  the  Transmission  of  Power  by  Ropes;  by  Iron  and 
Wood  Frictional  Gearing  ;  on  the  Strength  of  Belting  Leather ;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  By 
JOHN  H.  COOPER,  M.  E.  8vo #3-50 

CRAIK.— The  Practical  American  Millwright  and  MUler. 
By  DAVID  CRAIK,  Millwright.     Illustrated  by  numerous  wood  en- 
gravings and  two  folding  plates.     8vo (Scarce.) 


\ 
HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  9 

CROSS. — The  Cotton  Yarn  Spinner  : 

Showing  how  the  Preparation  should  be  arranged  for  Different 
Counts  of  Yarns  by  a  System  more  uniform  than  has  hitherto  been 
practiced ;  by  having  a  Standard  Schedule  from  which  we  make  all 
our  Changes.  By  RICHARD  CROSS.  122  pp.  I2mo.  .  75 

CRISTIANI. —  A  Technical  Treatise  on  Soap  and  Candles: 
With  a  Glance  at  the  Industry  of  Fats  and  Oils.     By  R.  S.  CRIS- 
TIANI, Chemist.     Author  of  "  Perfumery  and  Kindred  Arts."     Illus- 
trated by  176  engravings.     $81  pages,  8vo.  $15-00 

COURTNEY.— The  Boiler  Maker's  Assistant  in  Drawing, 
Templating,  and  Calculating  Boiler  Work  and  Tank 
Work,  etc. 

Revised  by  D.  K    CLARK.     102  ills.     Fifth  edition.     .         .         80 
COURTNEY.— The  Boiler  Maker's  Ready  Reckoner: 

With  Examples  of  Practical  Geometry  and  Templating.  Revised  by 
D.  K.  CLARK,  C.  E.  37  illustrations.  Fifth  edition.  •  $1.60 

DAVIDSON. — A  Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling,  and  Sign- Writing: 

Containing  full  information  on  the  processes  of  House  Painting  in 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Principles  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  W^ith  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A  DAVIDSON.  i2mo. 

$2.00 

DAVIES.— A  Treatise  on  Earthy  and  Other    Minerals   and 

Mining: 

By  D.  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  etc.  Illustrated  by 
76  Engravings.  I2mo.  ......  .  $$.OO 

DAVIES. — A  Treatise  on  Metalliferous  Minerals  and  Mining: 
By  D.  C.  DAVIES,  F.  G.  S  ,  Mining  Engineer,  Examiner  of  Mines, 
Quarries  and  Collieries.  Illustrated  by  148  engravings  of  Geological 
Formations,  Mining  Operations  and  Machinery,  drawn  from  the 
practice  of  all  parts  of  the  world.  Fifth  Edition,  thoroughly  Revised 
and  much  Enlarged  by  his  son,  E.  Henry  Davies.  I2mo.,  524 
pages  .......  .  $5'°° 

DAVIES. — A  Treatise  on  Slate  and  Slate  Quarrying: 

Scientific,  Practical  and  Commercial.  By  D.  C.  DAVIES,  F.  G.  S., 
Mining  Engineer,  etc.  W7ith  numerous  illustrations  and  folding 
plates.  I2mo  .  .  .  \  .  .  .  .  .  $I.2O 

DAVIS. — A  Practical  Treatise  on  the  Manufacture  of  Brick, 

Tiles  and  Terra-Cotta : 

Including  Stiff  Clay,  Dry  Clay,  Hand  Made,  Pressed  or  Front,  and 
Roadway  Paving  Brick,  Enamelled  Brick,  with  Glazes  and  Colors, 
Fire  Brick  and  Blocks.  Silica  Brick,  Carbon  Brick,  Glass  Pots,  Re- 


10          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

torts,  Architectural  Terra-Cotta,  Sewer  Pipe,  Drain  Tile,  Glazed  and 
Unglazed  Roofing  Tile,  Art  Tile,  Mosaics,  and  Imitation  of  Intarsia 
or  Inlaid  Surfaces.     Comprising  every  product  of  Clay  employed  in 
Architecture,  Engineering,  and  the  Blast  Furnace.      With  a  Detailed 
Descripiion    of  the    Different    Clays    employed,    the    Most    Modern 
Machinery,  Tools,  and  Kilns  used,  and  the  Processes  for  Handling, 
Disintegrating,  Tempering,  and  Moulding  the  Clay  into  Shape,  Dry- 
ing, Setting,  and  Burning.      By  Charles  Thomas  Davis.     Third  Edi- 
tion.    Revised    and    in   great    part    rewritten.     Illustrated    by    261 
engravings.     662  pages     .......         $S-°° 

DAVIS. — A  Treatise  on  Steam-Boiler  Incrustation  and  Meth- 
ods for  Preventing  Corrosion  and  the  Formation  of  Scale: 
By  CHARLES  T.  DAVIS.     Illustrated  by  65  engravings.     8vo. 
DAVIS. — The  Manufacture  of  Paper : 

Being  a  Description  of  the  various  Processes  for  the  Fabrication, 
Coloring  and  Finishing  of  every  kind  of  Paper,  Including  the  Dif- 
ferent Raw  Materials  and  the  Methods  for  Determining  their  Values, 
the  Tools,  Machines  and  Practical  Details  connected  with  an  intelli- 
gent and  a  profitable  prosecution  of  the  art,  with  special  reference  to 
the  best  American  Practice.  To  which  are  added  a  History  of  Pa- 
per, complete  Lists  of  Paper- Making  Materials,  List  of  American 
Machines,  Tools  and  Processes  used  in  treating  the  Raw  Materials, 
and  in  Making,  Coloring  and  Finishing  Paper.  By  CHARLES  T. 
DAVIS.  Illustrated  by  156  engravings.  608  pages,  8vo.  $6.00 
DAVIS. — The  Manufacture  of  Leather: 

Being  a  Description  of  all  the  Processes  for  the  Tanning  and  Tawing 
with  Bark,  Extracts,  Chrome  and  all  Modern  Tannages  in  General 
Use,  and  the  Currying,  Finishing  and  Dyeing  of  Every  Kind  of  Leather; 
Including  the  Various  Raw  Materials,  the  Tools,  Machines,  and  all 
Details  of  Importance  Connected  with  an  Intelligent  and  Profitable 
Prosecution  of  the  Art,  with  Special  Reference  to  the  Best  American 
Practice.  To  which  are  added  Lists  of  American  Patents  (1884-1897) 
for  Materials,  Processes,  Tools  and  Machines  for  Tanning,  Currying, 
etc.  By  CHARLES  THOMAS  DAVIS.  Second  Edition,  Revised,  and 
in  great  part  Rewritten.  Illustrated  by  147  engravings  and  14  Sam- 
ples of  Quebracho  Tanned  and  Aniline  Dyed  Leathers.  8 vo,  cloth, 

712  pages.     Price $7-S° 

DAWIDOWSKY— BRANNT.— A  Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilages, 
etc. : 

Eased  upon  Actual  Experience.  By  F.  DAWIDOWSKY,  Technical 
Chemist.  Translated  from  the  German,  with  extensive  additions, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM  T.  BRANNT,  Graduate  of  the  Royal  Agricultural  College 
of  Eldena,  Prussia.  35  Engravings.  I2mo.  .  .  .  $2.50 
DE  GRAFF.— The  Geometrical  Stair-Builders*  Guide : 

being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  its 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Steel 
Engravings ;  together  with  the  use  of  the  most  approved  principle* 
of  Practical  Geometry.  By  SIMON  DE  GRAFF,  Architect.  (Scarce.) 


HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE.        n 


DE  KONINCK— DIETZ.— A  Practical  Manual  of  Chemical 

Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DK 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.  S.  G.,  M.  I.  C.  E.,  etc.  American 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A. 
FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  .  $1.50 

DUNCAN.— Practical  Surveyor's  Guide: 

Containing  the  necessary  information  to  make  any  person  of  corm 
mon  capacity,  n  finished  land  surveyor  without  the  aid  of  a  teacher 
By  ANDREW  DUNCAN.  Revised.  72  engravings,  214 pp.  I2mo.  $1.50 

DUPLAIS. — A  Treatise  on  the   Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grnin,  Rice,  Potatoes,  Sorghum,  Aspho- 
del, Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy. 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aro- 
matic Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  the 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copious 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc«  etc,  Translated  and  Edited,  from  the  French  of  MM.  DUPLAIS, 
By  M.  McKENNiE,  M.  D.  Illustrated  743  pp.  8vo.  $15.00 

DYER  AND  COLOR-MAKER'S  COMPANION  : 

Containing  upwards  of  two  hundred  Receipts  for  making  Colors,  on 
the  most  approved  principles,  for  all  the  various  styles  and  fabrics  now 
in  evistence ;  with  the  Scouring  Process,  and  plain  Directions  for 
Preparing,  Washing-off,  and  Finishing  the  Goods.  I2mo.  $1  OO 

EIDHERR.— The  Techno-Chemical  Guide  to  Distillation: 
A  Hand-Book  for  the  Manufacture  of  Alcohol  and  Alcoholic  Liquors, 
including  the  Preparation  of  Malt  and  Compressed  Yeast.     Edited 
from  the  German  of  Ed.  Eidherr.    Fully  illustrated.    (In  preparation.) 

EDWARDS. — A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practicnl  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty-three  Engravings,  including  examples  of 
the  most  modern  Engines.  Third  edition,  thoroughly  revised,  with 
much  additional  matter.  12 mo.  414  pages  .  .  .  $2  OO 

£D  WARDS. — Modern  American  Locomotive  Engines, 
Their  Design,  Construction  and  Management.     By  EMORY  EDWARDS. 
Illustrated  I2mo $2.00 

EDWARDS. — The  American  Steam  Engineer: 

Theoretical  and  Practical,  with  examples  of  the  latest  and  most  ap- 
proved American  practice  in  the  design  and  construction  of  Steam 
Engines  and  Boilers.  For  the  use  of  engineers,  machinists,  boiler- 
«n«\kers,  and  engineering  students.  By  EMORY  EDWARDS.  Fully 
illustrated,  419  pages.  I2mo.  ....  #2.50 


12         HENRY  CAREY  BAIRD  &  CO.'S   CATALOGUE. 

EDWARDS.— Modern  American  Marine  Engines,  Boilers,  an& 

Screw  Propellers, 

Their  Design  and  Construction.  Showing  the  JPresent  Practice  ot 
the  most  Eminent  Engineers  and  Marine  Engine  Builders  in  the 
United  States.  Illustrated  by  30  large  and  elaborate  plates.  410.  $5.00 

EDWARDS. — The  Practical  Steam  Engineer's  Guide 

In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam  Pumps,  Boilers,  Injector^ 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and  Steam 
Gauges.  For  the  use  of  Engineers,  Firemen,  and  Steam  Users.  By 
EMORY  EDWARDS.  Illustrated  by  119  engravings.  A2O  pages, 
I2mo.  ..........  $2  50- 

EISSLER.— The  Metallurgy  of  Gold: 

A  Practical  Treatise  on  the  Metallurgical  Treatment  of  Gold-Bear- 
ing  Ores,  including  the  Processes  of  Concentration  and  Chlorination, 
and  the  Assaying,  Melting,  and  Refining  of  Gold.  By  M.  EISSLER. 

With  132  Illustrations.     I2mo $7'5°x 

EISSLER.— The  Metallurgy  of  Silver  : 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviati«>n 
of  Silver  Ores,  including  the  Assaying,  Melting,  and  Refining  of 
Silver  Bullion.  By  M.  EISSLER.  124  Illustrations.  336  pp. 

I2mo $4-25- 

ELDER. — Conversations  on  the  Principal  Subjects  of  Political 

Economy. 
By  DR.  WILLIAM  ELDER.     8vo $2.50 

ELDER. — Questions  of  the  Day, 

Economic  and  Social.     By  DR.  WILLIAM  ELDER.     8ro.     .      $3.00 
ERNI  AND  BROWN.— Mineralogy  Simplified. 

Easy  Methods  of  Identifying  Minerals,  including  Ores,  by  Means  of 
the  Blow-pipe,  by  Flame  Reactions,  by  Humid  Chemical  Analysis,, 
and  by  Physical  Tests.  By  HENRI  ERNI,  A.  M.,  M.  D.  Third  Edi- 
tion, revised,  re-arranged  and  with  the  addition  of  entirely  new  matter,, 
including  Tables  for  the  Determination  of  Minerals  by  Chemical  and 
Pyrognostic  Characters,  and  by  Physical  Characters.  By  AMOS  P. 
BROWN,  E.  M.,  Ph.  D.  350  pp.,  illustrated  by  96  engravings,  pocket- 
book  form,  full  flexible  morocco,  gilt  edges  .  .  .  #2.50- 
FAIRBAIRN.— The  Principles  of  Mechanism  and  Machinerj 

of  Transmission  • 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pultevs, 
Strength  and  Proportions  of  Shafts,  Coupling  of  Shafts,  and  Engag 
ing  and  Disengaging  Gear.  By  SIR  WILLIAM  FAIRBAIRN,  Bart 
C.  E.  Beautifully  illustrated  by  over  150  wood-cuts.  In  one 

Tolume.  I2mo #2.00- 

FLEMING. — Narrow  Gauge  Railways  in  America. 

A  Sketch  of  their  Rise,  Progress,  and  Success.     Valuable  Statistics 

as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  etc.     By 

HOWARD  FLEMING.     Illustrated,  8vo.      .         .         .        .        $i  oo 

FORSYTH.— Book  of  Designs  for  Headstones.   Mural,  and 

othtr  Monuments : 

Containing  78  Designs.  By  JAMES  FORSYTH.  sWith  an  Introduction 
Uy  CHARLES  BOUTELL,  M.  A.  4  to.,  cloth  .  .  -  $3-5°- 


HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE.        13 


FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu« 

facture  of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine: 
Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pesi,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical 
Manufacturer  of  Starch-Sugar.  Illustrated  by  58  engravings,  cover- 
ing every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  .  $3.50 

GARDNER. — The  Painter's  Encyclopaedia: 
Containing  Definitions  of  all  Important  Words  in  the  Art  of  Plain 
and  Artistic  Painting,  with  Details  of  Practice  in  Coach,  Carriage, 
Railway  Car,  House,  Sign,  and  Ornamental  Painting,  including 
Graining,  Marbling,  Staining,  Varnishing,  Polishing,  Lettering, 
Stenciling,  Gilding,  Bronzing,  etc.  By  FRANKLIN  B.  GARDNER. 
158  Illustrations.  I2mo.  427  pp.  .....  $2.00 

GARDNER.— Everybody's  Paint  Book: 

A  Complete  Guide  to  the  Art  of  Outdoor  and  Indoor  Painting.  38 
illustrations  12 mo,  183  pp.  ......  $1.00 

GEE.— The   Jeweller's    Assistant  in  the   Art  of  Working  in 

Gold: 
A  Practical  Treatise  for  Masters  and  Workmen.      I2mo.      .       $3-OO 

GEE. — The  Goldsmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting, and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste ;  Chemical  and  Physical  Properties  of  Gold ;  with  a  New 
System  of  Mixing  its  Alloys ;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  „  .  $1.25 

GEE. — The  Silversmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of  Refining  and  Melting  the  Metal;  its 
Solders ;  the  Preparation  of  Imitation  Alloys ;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste  ;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 
Memoranda.  By  GEORGE  E.  GEE.  Illustrated.  I2mo.  Si. 25 

GOTHIC  ALBUM  FOR  CABINET-MAKERS: 

Designs  for  Gothic  Furniture.     Twenty-three  plates.     Oblong  $1-5° 

GrRANT. — A  Handbook  on  the  Teeth  of  Gears  : 
Their  Curves,  Properties,  and  Practical  Construction.     By  GEORGE 
B.  GRANT.     Illustrated.     Third  Edition,  enlarged.     8vo.          $1.00 

GREENWOOD.— Steel  and  Iron: 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolling- 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN* 
WOOD,  F.  C.  S.  With  97  Diagrams,  536  pages.  I2mo.  $1.75 


14       HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE. 


GREGORY. — Mathematics  for  Practical  Men : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and' 
Civil  Engineers.     By  OLINTHUS  GREGORY.     8vo.,  plates         $3.00 

GRISWOLD. — Railroad  Engineer's  Pocket  Companion  for  thi 

Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En 
gineers;  also  the  Art  of  Levelling  from  Preliminary  Survey  to  th«- 
Construction  of  Railroads,  intended  Expressly  for  the  Young  En 
gineer,  together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  12010.,  tucks $1.50 

GRUNER. — Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  oi 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  author's  sanction,  with  an  Appendix,  by  L.  D. 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

Hand-Book  of  Useful  Tables  for  the  Lumberman,  Farmet  and 

Mechanic : 

Containing  Accurate  Tables  of  Logs  Reduced  to  Inch  Board  Meas- 
ure, Plank,  Scantling  and  Timber  Measure ;  Wages  and  Rent,  by 
Week  or  Month;  Capacity  of  Granaries,  Bins  and  Cisterns;  Land 
Measure,  Interest  Tables,  with  Directions  for  Finding  the  Interest  on 
any  sum  at  4,  5,  6,  7  and  8  per  cent.,  and  many  other  Useful  Tables. 
32  mo.,  boards.  186  pages .25 

HASERICK.— The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleaching  an'3.  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yarnt 
or  fabrics.  8vo $5-OO 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  HaUe*. 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  $1.25 

HERMANN. — Painting  on  Glass  and  Porcelain,  and  Enamel 

Painting: 

A  Complete  Introduction  to  the  Preparation  of  all  the  Colors  and 
Fluxes  Used  for  Painting  on  Glass,  Porcelain,  Enamel,  Faience  and 
Stoneware,  the  Color  Pastes  and  Colored  Glasses,  together  with  a 
Minute  Description  ot  the  Firing  ot  Colors  and  Enamels,  on  the 
Basis  of  Personal  Practical  Experience  of  the  Art  up  to  Date.  I& 
illustrations.  Second  edition. 

HAUPT. — Street  Railway  Motors: 

With  Descriptions  and  Cost  of  Plants  and  Operation  of  the  Variour 
Systems  now  in  Use.  I2t«^.  »  $17S- 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         15 

HAUPT. — A  Manual  of  Engineering  Specifications  and  Con- 
tracts. 

By  LEWIS  M.  HAUPT,  C.  E.  Illustrated  with  numerous  maps. 
328pp.  8vo $3  oo 

HAUPT.— The  Topographer,  His  Instruments  and  Methods. 
By  LEWIS  M.  HAUPT,  A.  M.,  C.  E.  Illustrated  with  numerous 
plates,  maps  and  engravings.  247  pp.  8vo.  .  .  .  $3.00 

HUGHES.— American  Miller  and  Millwright's  Assistant: 
By  WILLIAM  CARTER  HUGHES.    I2mo $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing  : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich;  the  Royal  Military  College,  Sandhurst ;  the  Indian  Civil  En- 
gineering College,  Cooper's  Hill  ;  Indian  Public  Works  and  Tele- 
graph Departments;  Royal  Marine  Lisjht  Infantry;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 
examples.  Small  quartc «  $1.50 

JERVIS.— Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property  ;  as  well  as  Railway  Managers,  Offi 
cers,  and  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  ihe 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  $2.oc 

KEENE. — A  Hand-Book  of  Practical  Gauging: 
For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla 
tion,  describing  the  process  in   operation   at  the  Custom-House  foi 
ascertaining  the  Strength  of  Wines.     By  JAMES  B.  KEENE,  of  H.  M. 
Customs.     8vo. $1  00 

KELLEY.— Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 
By  HON.  WILLIAM  D.  KELLEY,  M.  C.     544  pages,  8vo.  .        $2.50 

KELLOGG.— A  New  Monetary  System  : 

The  only  means  of  Securing  the  respective  Rights  of  Labor  and 
Property,  and  of  Protecting  the  Public  from  Financial  Revulsions. 
By  EDWARD  KELLOGG.  I2mo.  Paper  cover,  #1.00.  Bound  in 
cloth $1.25 

KEMLO.— Watch- Repairer's  Hand-Book : 
Bein^  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apar 
Pulling  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  Foreign  Watches,  and  all  American  Watches.     By  F.  KEMLO, 
Practical  WatrVimaker.     With  Illustrations.     I2mo.  .         $1.25 


16          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

KENTISH.— A  Treatise  on  a  Box  of  Instruments, 

And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Loga 
rithms,  including  Practical  Geometry,  Surveying,  Measuring  of  Tim- 
ber, Cask  and  Malt  Gauging,  Heights,  and  Distances.  By  THOMA* 
KENTISH.  In  one  volume.  i2mo.  .  .  .  .  $1.00 

KERL.— The  Assayer's  Manual: 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.  By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines.  Translated  from  the  German  by 
WILLIAM  T.  BRANNT.  Second  American  edition,  edited  with  Ex- 
tensive Additions  by  F.  LYNWOOD  GARRISON,  Member  of  the 
American  Institute  of  Mining  Engineers,  etc.  Illustrated  by  87  en- 
gravings. 8vo.  (Scarce.^) 
KICK. —Flour  Manufacture . 

A  Treatise  on  Milling  Science  and  Practice.  By  FREDERICK  KICK 
Imperial  Regierungsrath,  Professor  of  Mechanical  Technology  in  tht 
imperial  German  Polytechnic  Institute,  Prague.  Translated  from 
the  second  enlarged  and  revised  edition  with  supplement  by  H.  H. 
P.  POWLES,  Assoc.  Memb.  Institution  of  Civil  Engineers.  Illustrated 
with  28  Plates,  and  167  Wood-cuts.  367  pages.  8vo.  .  $10.00 
KINGZETT. — The  History,  Products,  and  Processes  of  the 

Alkali  Trade : 

Including  the  most  Recent  Improvements.     By  CHARLES  THOMAS 
v.vr.7ETT  Consulting  Chemist.    With  23  illustrations.    8vo.       $2.50 
KIRK.— The  Cupola  Furnace  : 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foundry 
Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter,  Con- 
sulting Expert  in  Melting.  Author  of  "The  Founding  of  Metals." 
Illustrated  by  78  engravings.  8vo.  379  pages.  .  .  $3-S° 
LANDRIN.— A  Treatise  on  Steel : 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.  From  the  French,  by  A.  A. 

FESQUET.     i2mo #2.50 

LANGBEIN.— A   Complete  Treatise  on  the  Electro-Deposi. 

tion  of  Metals  : 

Comprising  Electro-Plating  and  Galvanoplastic  Operations,  the  De- 
position of  Metals  by  the  Contact  and  Immersion  Processes,  the  Color- 
ing of  Metals,  the  Methods  of  Grinding  and  Polishing,  as  well  as 
Descriptions  of  the  Electric  Elements,  Dynamo-Electric  Machines, 
Thermo-Piles  and  of  the  Materials  and  Processes  used  in  Every  De- 
partment of  the  Art.  From  the  German  of  DR.  GEORGE  LANGBEIN, 
with  additions  by  WM.  T.  BRANNT.  Fourth  Edition,  thoroughly  revised 
and  much  enlarged.  150  Engravings.  590  pages.  8vo.  1902.  $4.00 

LARDNER. — The  Steam-Engine  : 

For  the  Use  of  Beginrters.     Illustrated.     I2mo.    ...        .60 

LEHNER.— The  Manufacture  of  Ink: 

Comprising  the  Raw  Materials,  and  the  Preparation  df  Waiting, 
Copying  and  Hektograph  Inks,  Safety  Inks,  Ink  Extracts  and  Pow- 
ders, etc.  Translated  from  the  German  of  SlGMUND  LEHNER,  with 
additions  by  WILLIAM  T.  BRANNT.  Illustrated.  12010.  $2:00 


HENRY   CAREV    BAIRD   &   <XX'S   CATALOGUE.        17 

L ARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide ; 
A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  Aft4 
their  Alloys,  etc. ;  to  which  are  added  Recent  Improvements  in  th« 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  By 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  in 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  New  edition, 
revised,  with  extensive  additions.  414  pages.  I2mo.  .  $2.50 

LEROUX. — A    Practical     Treatise    on    the    Manufacture    of 

Worsteds  and  Carded  Yarns  : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  the 
International  Jury,  and  of  the  Artisans  selected  by  the  Commttte; 
appointed  by  the  Council  of  the  Society  of  Arts,  London,  on  Woolen 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni« 
versa!  Exposition,  1867.  8vo.  $5.00 

LEFFEL.— The  Construction  of  Mill-Dams  : 
Comprising  also  the  Building  of  Race  and  Reservoir  Embankments 
and   Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Water 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo. $2.50 

LESLIE. — Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thomsand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  I2mo $1.50 

LE  VAN. — The  Steam  Engine  and  the  Indicator : 

Their  Origin  and  Progressive  Development ;  including  the  Most 
Recent  Examples  of  Steam  and  Gas  Motors,  together  with  the  Indi- 
cator, its  Principles,  its  Utility,  and  its  Application.  By  WILLIAM 
BARNET  LE  VAN.  Illustrated  by  205  Engravings,  chiefly  of  Indi- 
cator-Cards. 469  pp.  8vo.  ......  $4-°° 

LIEBER. — Assayer's  Guide  : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
the  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  Revised.  283  pp.  I2mc.  $1.50 

Lockwood's  Dictionary  of  Terms  : 

Used  in  the  Practice  of  Mechanical  Engineering,  embracing  those 
Current  in  the  Drawing  Office,  Pattern  Shop,  Foundry,  Fitting,  Turn- 
Ing,  Smith's  and  Boiler  Shops,  etc.,  etc.,  comprising  upwards  of  Six 
Thousand  IVfinitions.  Edited  by  a  Foreman  Pattern  Maker,  author 
of  "  Patter  Making."  417  pp.  I2mo.  ,  »  . 


IS         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

LUKIN.— The  Lathe  and  Its  Uses  : 

Or  Instruction  in  the  Art  of  Turning  Wood  and  Metal.  Including 
a  Description  of  the  Most  Modern  Appliances  for  the  Ornamentation 
of  Plane  and  Curved  Surfaces,  an  Entirely  Novel  Form  of  Lathe 
for  Eccentric  and  Rose-Engine  Turning;  A  Lathe  and  Planing 
Machine  Combined;  and  Other  Valuable  Matter  Relating  to  the 
Art.  Illustrated  by  462  engravings.  Seventh  edition.  315  pages. 
Svo #4.25 

MAIN  and  BROWN. — Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And  Examination  Paper.-.;  with  Hints  for  their  Solution.  By 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal  "tfaval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.  I2mo.,  cloth  .  $1.00 

MAIN  and  BROWN.— The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.  MAIN,   M.  A.  F.  R.,  Ass't    S.   Professor   Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineer 
R.  N.,  attached  to  the  R.  N.  College.     Illustrated.     8vu.  . 

MAIN  and  BROWN.— The  Marine  Steam-Engine. 
By  THOMAS  J.  MAIN,  F.  R.  Ass't  .S.  Mathematical  Professor  at  the 
Royal    Naval    College,   Portsmouth,  and   THOMAS    BROWN,   Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.     Attached  to  the  Royal  Naval 
College.     With  numerous  illustrations.     Svo. 

MAKINS.— A  Manual  of  Metallurgy: 

By  GEORGE  HOGARTH  MAKINS.  100  engravings.  Second  edition 
rewritten  and  much  enlarged.  I2mo..  592  pages 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Mechanic*) 
Engineers  : 

Showing  the  Proper  Arrangement  of  tiVheels  for  Cutting  the  Threads 
of  Screws  of  any  Required  Pitch;  with  a  Table  for  Making  the  Uni 
versal  Gas-Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 
Svo .50 

MICHELL.— Mine  Drainage: 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under 
ground  Steam  Pumping  Machinery.  With  a  Description  of  a  large 
number  of  the  best  known  Engines,  their  General  Utility  and  th« 
Special  Sphere  of  their  Action,  the  Mode  of  their  Application,  and 
their  Merits  compared  with  other  Pumping  Machinery.  By  STEPHEJt 
MICHELL.  Illustrated  by  247  engravings.  8vo.,  369  pages.  $12.50 

MOLESWORTH.— Pocket-Book   of    Useful    Formulae   and 
Memoranda  for  Civil  and  Mechanical  Engineers. 
By  GUILFORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Railway.     Full- 
bound  in  Pocket-book  form $1.00 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          19 

MOORE.— The  Universal  Assistant  and  the  Complete  Me 

chanic : 

Containing  over  one  million  Industrial  Facts,  Calculations,  Receipt^ 
Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
in  every  occupation,  from  the  Household  to  the  Manufactory.  By 
R.  MOORE.  Illustrated  by  500  Engravings.  I2mo.  .  $2.50 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks  : 
By  means  of  the  Prismoidal  Formula.  Illustrated  with  Numerous 
Wood-Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas. 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyors 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork 

By  ELWOOD  MORRIS,  C.  E.    8vo #1.50 

MAUCHLINE.— The  Mine  Foreman's  Hand-Book 

Of  Practical  and  Theoretical  Information  on  the  Opening,  Venti- 
lating, and  Working  of  Collieries.  Questions  and  Answers  on  Prac- 
tical and  Theoretical  Coal  Mining.  Designed  to  Assist  Students  and 
Others  in  Parsing  Examinations  for  Mine  Foremanships.  By 
ROBERT  MAUCHLINE,  Ex-Inspector  of  Mines.  A  New,  Revised  and 
Enlarged  Edition.  Illustrated  by  114  engrarings.  8vo.  337 

Pages #3.75 

NAPIER.— A  System  of  Chemistry  Applied  to  Dyeing. 
By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Edi* 
tion.  Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar  Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus- 
trated. 8vo.  422  pages $3.00 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formulae,  foi 
finding  the  Discharge  of  Water  from  Orifices,  Notches, 
Weirs,  Pipes,  and  Rivers : 

Third  Edition,  with  Additions,  consisting  of  New  Formulae  for  the 
Discharge  from  Tidal  and  Flood  Sluices  and  Siphons;  general  infor 
mation  on  Rainfall,  Catchment-Basins,  Drainage,  Sewerage,  Wa;e» 
Supply  for  Towns  and  Mill  Power.  Bv  TORN  NEVILLE.  C.  E.  M  R 
I.  A. ;  Fellow  of  the  Royal  Geological  Society  of  Ireland.  Thick 

I2mo $5.50 

NEWBERY.—  Gleanings     from     Ornamental     Art    of     every 

style : 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
1862,  and  the  best  English  and  Foreign  works.  In  a  series  of  loo 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  By 
ROBERT  NEWBERY.  410.  .  .  .  .  ,  .  (Scarce.J 

tf  ICHOLLS.  -The  Theoretical  and  Practical  Boiler-Maker  an* 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor 
Foremen  a*\d  Working;  Boiler-Makers.  Iron,  Copper,  and  Tinsmiths 


20        HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

Draughtsmen,  Engineers,  the  General  Steam-using  Public,  and  for  the 
Use  of  Science  Schools  and  Classes.  By  SAMUEL  NICHOLLS.  Illus- 
trated by  sixteen  plates,  I2mo. $2.50 

NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding : 

Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gliding,  and  Finishing.  Also,  the  Art  of  Marbling  Book-edges  and 
Paper.  By  JAMES  B.  NICHOLSON.  Illustrated.  I2mo.,  cloth  #2.25 

NJCOLLS.— The  Railway  Builder: 

A  Hand-Book  for  Estimating  the  Probable  Cost  of  American  Rail- 
way Construction  and  Equipment.  By  WILLIAM  J.  NicoLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form  .  $2.00 

NORMANDY.— The  Commercial  Handbook  of  Chemical  An- 

alysis : 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  01 
Commercial  Value  of  Substances  used  in  Manufactures,  in  Trades, 
and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
to  a  great  extent  rewritten.  By  HENRY  M.  NOAD,  Ph.D.,  F.R.S., 
thick  I2mo Scarce 

N ORRIS. — A  Handbook  fcr  Locomotive   Engineers  and  Ma- 
chinists : 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco- 
motives; Manner  of  Setting  Valves;  Tables  of  Squares,  Cubes,  Areas, 
etc.,  etc.  By  SEPTIMUS  NORRIS,  M.  E.  New  edition.  Illustrated, 
I2mo jjU.5<3 

NYSTROM.— A  New  Treatise  on  Elements  of  Mechanics  : 
Establishing  Strict  Precision  in  the  Meaning  of  Dynamical  Terms : 
accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me 
trology.     By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo.        $3.0* 

NYSTROM. — On  Technological  Education  and  the  Construc- 
tion of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  laU 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi 
tional  matter.  Illustrated  by  seven  engravings.  I2mo.  .  $1.2 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 

Containing  a  brief  account  of  all  the  Substances  and  Processes  u 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  Practical 
Receipts  and  Scientific  Information.  By  CHARLES  O'NEILL,  Analy 
deal  Chemist.  To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.  By  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867-  8vo.( 
491  pages  .  $3.00 

ORTON. — Underground  Treasures*. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
of  all  the  Useful  Minerals  within  the  United  States.  By  JAMES 
ORTON,  A.M.,  Late  Professor  of  Natural  History  in  Vassar  College. 
N.  Y.;  author  of  the  "Andes  and  the  Amazon,"  etc.  A  New  Edi- 
tion, with  An  Appendix, on  Ore  Deposits  and  Testing  Minerals  (1901). 
Illustrated .  .  £1.50 


HENRY    CAREY    BAIRD   &   CO.'S   CATALOGUE.        21 


OSBORN.— The  Prospector's  Field  Book  and  Guide. 

In  the  Search  For  and  the  Easy  Determination  of  Ores  and  Other 
Useful  Minerals.  By  Prof.  H.  S.  OSBORN,  LL.  D.  Illustrated  by  58 
Engravings.  I2mo.  Fifth  Edition.  Revised  and  Enlarged 

(i901) $1.50 

OSBORN— A  Practical  Manual  of  Minerals,  Mines  and  Min 

ing: 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and  Associations  of  the  Useful  Minerals;  their  Methods  of 
Chemical  Analysis  and  Assay  ;  together  with  Various  Systems  of  Ex- 
cavating and  Timbering,  Brick  and  Masonry  Work,  during  Driving, 
Lining,  Bracing  and  other  Operations,  etc.  By  Prof.  H.  S.  OSBORN, 
LL.  D.,  Author  of  "  The  Prospector's  Field- Book  and  Guide."  171 
engravings.  Second  Edition,  revised.  8vo.  .  .  .  $4-5° 
OVERMAN.— The  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware,  of  Steel  and    Iron,  and  for  Men   of  Science  and  Art.     By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  lion,"  etc.     A  new,  enlarged,  and  revised  Edition.     By 
A.  A.  FESQLiET,  Chemist  and  Engineer.     I2mo.         .         .         $1.50 
OVERMAN.— The  Moulder's  and  Founder's  Pocket  Guide  : 
A  Treatise  or*  Moulding  and  Founding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow- 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues;  Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals;  Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.     By  FREDERICK  OVERMAN,  M.  E.     A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
Ordnance,  Malleable  Iron  Castings,  etc.     By  A.  A.  FESQUET,  Chem- 
ist and  Engineer.     Illustrated  by  44  engravings.     I2mo.    .        $2.00 
PAINTER,  GILDER,  AND  VARNISHER'S  COMPANION. 
Comprising  the  Manufacture  and  Test  of  Pigments,  the  Arts  of  Paint- 
ing, Graining,  Marbling,  Staining,  Sign- writing,  Varnishing,  Glass- 
staining,  and   Gilding  on  Glass ;   together  with  Coach  Painting  and 
Varnishing,   and  the    Principles    of  the  Harmony  and  Contrast  of 
Colors.     Twenty-seventh  Edition.     Revised,  Enlarged,  and  in  great 
part  Rewritten.     By  WILLIAM  T.  BRANNT,  Editor  of  "  Varnishes, 
Lacquers,  Printing  Inks  and  Sealing  Waxes."     Illustrated.     395  pp. 

I2mo.  , $1.50 

PALLETT. — The  Miller's,  Millwright's,  and  Engineer's  Guide. 
By  HENRY  PALLETT.     Illustrated.     i2mo.       .        .        .        #2.00 


22         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

PERCY.— The  Manufacture  of  Russian  Sheet-Iron. 
By  JOHN  PERCY,  M.  D.,  F.  R.  S.     Paper.      ...        25  cts. 

PERKINS.— Gas  and  Ventilation: 

Practical  Treatise  on  Gas  and  Ventilation.    Illustrated.    I2mo.    $1.25 

PERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

and  Boiler  Plate  Roller : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and  Piles 
to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron;  the  Thickness  of  the  Bar  Gauge 
in  decimals ;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  112  Ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 

#1.50 

POSSELT. — Recent  Improvements  in  Textile  Machinery  Re- 
lating to  Weaving : 

Giving  the  Most  Modern  Points  on  the  Construction  of  all  Kinds 
of  Looms,  Warpers,  Beamers,  Slashers,  Winders,  Spoolers,  Reeds, 
Temples,  Shuttles,  Bobbins,  Heddles,  Heddle  Frames,  Tickers, 
Jacquards,  Card  Stampers,  etc.,  etc.  600  illus.  .  .  $3  oo 

POSSELT. — Technology  of  Textile  Design: 
The  Most  Complete  Treatise  on  the  Construction  and  Application 
of  Weaves  for  all  Textile  Fabrics  and  the  Analysis  of  Cloth.     By  E. 
A.  Posselt.     1,500  illustrations.     410 #5.00 

POSSELT.— Textile  Calculations: 

A  Guide  to  Calculations  Relating  to  the  Manufacture  of  all  Kinds 
of  Yarns  and  Fabrics,  the  Analysis  of  Cloth,  Speed,  Power  and  Belt 
Calculations.  By  E.  A.  POSSELT.  Illustrated.  410.  .  $2.00 

REGNAULt.— Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  #6.00 

RICHARDS. — Aluminium : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illust.  Third  edition,  enlarged  and  revised  (1895)  .  $6.OO 

RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting  : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors;  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessary  Apparatus  and  Directions  for  its  Use ;  Dryers ;  th» 
Testing.  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
B  IFFAULT,  VERGNAUD,  and  TOUSSAINT.  Revised  and  Edited  by  M. 


HENRY  CAREV  BAIRD  &  CO.'S  CATALOGUE.          23 


F.  MALEPEYRE.    Translated  from  the  French,  by  A.  A. 

Chemist  and  Engineer.     Illustrated  by  Eighty  engravings.     In  one 

vol.,  8vo.,  659  pages          .         .         .....        £5.00 

ROPER.—  A  Catechism  of  High-Pressure,  or  Non-Condensing 

Steam  -Engines  : 

Including  the  Modelling,  Constructing,  and  Management  of  Steam- 
Engines  and  Steam  Boilers.  With  valuable  illustrations.  By  STE- 
PHEN ROPER,  Engineer.  Sixteenth  edition,  revised  and  enlarged. 
i8mo.,  tucks,  gilt  edge  .  .....  $2.OO 

ROPER.  —  Engineer's  Handy-Book: 

Containing  a  full  Explanation  of  the  Steam-Engine  Indicator,  and  its 
Use  and  Advantages  to  Engineers  and  Steam  Users.  With  Formulas 
for  Estimating  the  Power  of  all  Classes  of  Steam-Engines  ;  also, 
Facts,  Figures,  Questions,  and  Tables  for  Engineers  who  wish  to 
qualify  themselves  for  the  United  States  Navy,  the  Revenue  Service, 
the  Mercantile  Marine,  or  to  take  charge  of  the  Better  Class  of  Sta- 
tionary Steam-Engines.  Tenth  edition.  i6mo.,  690  pages,  tucks, 
gilt  edge  ..........  $3.50 

ROPER.  —  Hand-Book  of  Land  and  Marine  Engines  : 
Including  the  Modelling,  Construction,   Running,  and  Management 
of  Lane1  and  Marine  Engines  and  Boilers.     With  illustrations.     By 
STEPHEN  ROPER,  Engineer.    Sixth  edition.     I2mo.,ti'cks,  gilt  edge. 

#3-5' 
ROPER.—  Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion,   Management,    and    Running   of  Locomotives.     By    STEPHEN 
ROPER.     Eleventh  edition.     i8mo.,  tucks,  gilt  edge  .         $2.50 

ROPER.  —  Hand-Book  of  Modern  Steam  Fire-Engines. 
With  illustrations.     By  STEPHEN  ROPER,  Engineer.     Fourth  edition, 
1  2mo.,  tucks,  gilt  edge       .         .         .         .         .         .         .         $3-5<J 

ROPER.  —  Questions  and  Answers  for  Engineers. 

This  little  book  contains  all  the  Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or- 
dinary intelligence  may  commit  them  to  memory  in  a  short  time.     By 
STEPHEN  ROPER,  Engineer.     Third  edition       .         .         .         $2.00 
ROPER.  —  Use  and  Abuse  of  the  Steam  Boiler. 

By  STEPHEN  ROPER,  Engineer.     Eighth  edition,  with  illustrations. 
l8mo.,  tucks,  gilt  edge       .......         $2.00 

ROSE.  —  The  Complete  Practical  Machinist  : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools. 
Tool  Grinding,  Marking  out  Work,  Machine  Tools,  etc.  By  JOSHUA 
ROSE.  395  Engravings.  Nineteenth  Edition,  greatly  Enlarged  with 
New  and  Valuable  Matter.  I2mo.,  504  pages.  .  .  $2.50 
ROSE.  —  Mechanical  Drawing  Self-Taught  : 

Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Instruments,  Elementarv  Instruction  in   Practical  Mechanical  Draw- 


24         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

ing,  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
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By  THOMAS  W.  SILI.OWAY  and  GEORGE  M.  HARDING,  Architects. 
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SHUNK. — A  Practical  Treatise  on  Railway  Curves  and  Loca- 
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SLOAN. — Homestead  Architecture  : 

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SLOANE. — Ho^e  Experiments  in  Science. 

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HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          25 

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Gardens.  By  CHARLES  H.  J.  SMITH,  Landscape  Gardener  and 
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SMITH.— The  Dyer's  Instructor: 

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SMYTH. — A  Rudimentary  Treatise  on  Coal  and  Coal-Mining. 
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SNIVELY. — The  Elements  of  Systematic  Qualitative  chemical 

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STOKES. — The  Cabinet-Maker  and  Upholsterer's  Companion-. 
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SHERRATT.— The  Elements  of  Hand-Railing  : 

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ifi         HENRY  CAREY  BAIRt,  &  CO.'S  CATALOGUE. 

SYME. — Outlines  of  an  Industrial  Science. 

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TAYLOR.— Statistics  of  Coal : 

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MAN.  Illustrated  by  five  Maps  and  many  wood  engravings.  8vo., 
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TEMPLETON. — The  Practical  Examinator  on  Steam  and  the 

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THAUSING.— The  Theory  and  Practice  of  the  Preparation  of 

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at  the  School  for  Brewers,  and  at  the  Agricultural  Institute,  Modling, 
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Thoroughly  and  elaborately  edited,  with  much  American  matter,  and 
according  to  the  latest  and  most  Scientific  Practice,  by  A.  SCHWARZ 
and  DR.  A.  H.  BAUER.  Illustrated  by  140  Engravings.  8vo.,  815 
pages  .  .  .  .  .  .  .  .  .  $10.00 

THOMPSON. — Political  Economy.     With  Especial  Reference 

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TURNER'S  (THE)  COMPANION: 

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HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          27 

"VAILE. — Galvanized- Iron  Cornice-Worker's  Manual: 

Containing  Instructions  in  Laying  out  the  Different  Mitres,  and 
Making  Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also, 
Tables  of  Weights,  Areas  and  Circumferences  of  Circles,  and  othet 
Matter  calculated  to  Benefit  the  Trade.  By  CHARLES  A.  VAILE. 
Illustrated  by  twenty-one  plates.  4*0.  .  .  .  .  $5.00 

VILLE. — On  Artificial  Manures  : 

Their  Chemical  Selection  and  Scientific  Application  to  Agriculture. 
A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VILLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 
engravings.  8vo.,  450  pages  .  .  .  .  .  .  $6.00 

'VILLE. — The  School  of  Chemical  Manures  : 

Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.  From 
the  French  of  M.  GEO.  VILLE,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer. With  Illustrations.  I2tno.  .  .  .  .  $1.25 

"VOGDES. — The  Architect's  and  Builder's  Pocket- Companion 

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3rick,  Cement  and  Concretes,  Quantities  of  Materials  in  given  Sizes 
and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
Bills  of  Prices  for  Carpenter's  Work  and  Painting ;  also,  Rules  for 
Computing  and  Valuing  Brick  and  Brick  Work,  Stone  Work,  Paint- 
Ing,  Plastering,  with  a  Vocabulary  of  Technical  Terms,  etc.  By 
FRANK  W.  VOGDES,  Architect,  Indianapolis,  Ind.  Enlarged,  revised, 
and  corrected.  In  one  volume,  368  pages,  full-bound,  pocket-book 

form,  gilt  edges $2.00 

Cloth         .  1.50 

'VAN  CLEVE.— The  English  and  American  Mechanic : 

Comprising  a  Collection  of  Over  Three  Thousand  Receipts,  Rules, 
and  Tables,  designed  for  the  Use  of  every  Mechanic  and  Manufac- 
turer. By  B.  FRANK  VAN  CLEVE.  Illustrated.  500  pp.  I2mo.  $2.00 

-WAHNSCHAFFE. — A  Guide  to  the  Scientific  Examination 

of  Soils: 

Comprising  Select  Methods  of  Mechanical  and  Chemical  Analysif 
and  Physical  Investigation.  Translated  from  the  German  of  Dr.  F, 
WAHNSCHAFFE.  With  additions  by  WILLIAM  T.  BRANNT.  Illus- 
trated by  25  engravings.  I2mo.  177  pages  .  .  .  $l-9& 

VWALL. — Practical  Graining : 

With  Descriptions  of  Colors  Employed  and  Tools  Used.  Illustrated 
by  47  Colored  Plates,  Representing  the  Various  Woods  Used  X 
Interior  Finishing.  By  WILLIAM  E.  WALL.  8vo.  (Scarce.) 

WALTON.— Coal-Mining  Described  and  Illustrated: 

By  THOMAS  H.  WALTON,  Mining  Engineer.  Illustrated  by  24  ?argf 
and  elaborate  Plates,  after  Actual  Workings  and  Apparatus.  £5.00 


28         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

WARE.— The  Sugar  Beet. 

Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varieties 
of  the  Sugar  Beet,  Examination,  Soils,  Tillage,  Seeds  and  Sowing, 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserva 
tion,  Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWI? 
S.  WARE,  C.  E.,  M.  E.  Illustrated  by  ninety  engravings.  8vo. 

#4.00 

WARN.— The  Sheet-Metal  Worker's  Instructor: 

For  Zinc,  Sheet-Iron,  Copper,  and  Tin-Plate  Workers,  etc.  Contain- 
ing a  selection  of  Geometrical  Problems ;  also,  Practical  and  Simple 
Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin-Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty- 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  .  $3-OO 

WARNER.— New  Theorems,  Tables,  and  Diagrams,  for  the 
Computation  of  Earth-work : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profes* 
sional  Computers.  In  two  parts,  with  an  Appendix.  Part  I.  A  Prac- 
tical Treatise;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix, 
Containing  Notes  to  the  Rules  and  Examples  of  Part  I.;  Explana- 
tions of  the  Construction  of  Scales,  Tables,  and  Diagrams,  and  9 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights. 
By  JOHN  WARNER,  A.  M.,  Mining  and  Mechanical  Engineer.  Illus- 
trated by  14  Plates.  8vo $3.00 

WILSON. — Carpentry  and  Joinery: 

By  JOHN  WILSON,  Lecturer  on  Building  Construction,  Carpentry  andi 
Joinery,  etc.,  in  the  Manchester  Technical  School.  Third  Edition,, 
with  65  full  page  plates,  in  flexible  cover,  oblong  .  .  .80- 

WATSON. — A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds. 
Ivory,  Bone  and  Precious  Woods;  Dyeing,  Coloring,  and  French 
Polishing;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  Bf 
EGBERT  P.  WATSON,  Author  of  "  The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON.— The  Modern  Practice  of  American  Machinists  and 

Engineers 

Including  the  Construction,  Application,  and  Use  of  Drills,  LatVic 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow-work  generally ,  with 
the  most  Economical  Speed  for  the  same;  the  Results  verified  bj 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  Floor.  Togetho 


HENRY   CAREY   BAIRD   &   CO.'S   CATALOGUE.        29 


with  Workshop  Management,  Economy  of  Manufacture,  the  Steam 
Engine,  Boilers,  Gears,  Belting,  etc.,  etc.  By  EGBERT  P.  WATSON. 
Illustrated  by  eighty-six  engravings.  I2mo.  .  .  .  £2.50 

WATT.— The  Art  of  Soap  Making  : 

A  Practical  Hand-Book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.  Fifth  Edition,  Revised,  to  which  is  added  an 
Appendix  on  Modern  Candle  Making.  By  ALEXANDER  WATT. 
111.  I2mo $3.00 

WEATHERLY.— Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
tallizing, Lozenge-making,  Comfits,  Gum  Goods, 
And  other  processes  for  Confectionery,  etc.,  in  which  are  explained, 
in  an  easy  and  familiar  manner,  the  various  Methods  of  Manufactur- 
ing every  Description  of  Raw  and  Refined  Sugar  Goods,  as  sold  by 
Confectioners  and  others.  I2mo.  .....  $1.50 

WILL.— Tables  of  Qualitative  Chemical  Analysis: 

With  an  Introductory  Chapter  on  the  Course  of  Analysis.  By  Pro- 
fessor HEINRICH  WILL,  of  Giessen,  Germany.  Third  American, 
from  the  eleventh  German  edition.  Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle, 
Pa.  8vo.  .  .  ...  .  .  .  $1.50 

WILLIAMS.— On  Heat  and  Steam  : 

Embracing  New  Views  of  Vaporization,  Condensation  and  Explo- 
sion. By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated.  8vo. 

$2.50 

WILSON. — First  Principles  of  Political  Economy: 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization. 
By  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo.  .......  $1-5° 

WILSON. — The  Practical  Tool-Maker  and  Designer: 

A  Treatise  upon  the  Designing  of  Tools  and  Fixtures  for  Machine 
Tools  and  Metal  Working  Machinery,  Comprising  Modern  Examples 
of  Machines  with  Fundamental  Designs  for  Tools  for  the  Actual  Pro- 
duction of  the  work;  Together  with  Special  Reference  to  a  Set  of 
Tools  for  Machining  the  Various  Parts  of  a  Bicycle.  Illustrated  by 
189  engravings.  1898.  .......  $2.50 

CONTENTS  :  Introductory.  Chapter  I.  Modern  Tool  Room  and  Equipment. 
II.  Files,  Their  Use  and  Abuse.  III.  Steel  and  Tempering.  IV.  Making  Jigs. 
'V.  Milling  Machine  Fixtures.  VI.  Tools  and  Fixtures  for  Screw  Machines.  VII. 
Broaching.  VIII.  Punches  and  Dies  for  Cutting  and  Drop  Press.  IX.  Tools  for 
Hollow-Ware.  X.  Embossing  :  Metal,  Coin,  and  Stamped  Sheet-Metal  Orna- 
ments. XI.  Drop  Forging.  XII.  Solid  Drawn  Shells  or  Ferrules;  Cupping  or 
Cutting,  and  Drawing  ;  Breaking  Down  Shells.  XIII.  Annealing,  Pickling  and 
Cleaning.  XIV.  Tools  for  Draw  Bench.  XV.  Cutting  and  Assembling  Pieces 
by  Means  of  Ratchet  Dial  Plates  at  One  Operation.  XVI.  The  Header.  XVII. 
Tools  for  Fox  Lathe.  XVIII.  Suggestions  for  a  Set  of  Tools  for  Machining  the 
Various  Parts  of  a  Bicycle.  XIX.  The  Plater's  Dynamo.  XX.  Conclusion— 
With  a  Few  Random  Ideas.  Appendix.  Index. 

WOODS. — Compound  Locomotives: 

By  ARTHUR  TANNATT  WOODS.  Second  edition,  revised  and  enlarged 
by  DAVID  LEONARD  BARNES,  A  M.f  C.  E.  8vo.  330  pp.  $3.0? 


jo        HENRY    CAREY   BAIRD   &    CO.'S  CATALOGUE. 


WOHLER.— A  Hand-Bookof  Mineral  Analysis: 

By  F.  WOHLER,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen.  Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated. 
I2mo. 

WORSSAM.— On  Mechanical  Saws  : 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  $1.50 


RECENT   ADDITIONS. 

BRANNT. — Varnishes,  Lacquers,  Printing  Inks  and  Sealing-1 
Waxes : 

Their  Raw  Materials  and  their  Manufacture,  to  which  is  added  the 
Art  of  Varnishing  and  Lacquering,  including  the  Preparation  of  Put- 
ties and  of  Stains  for  Wood,  Ivory,  Bone,  Horn,  and  Leather.  By 
WILLIAM  T.  BRANNT.  Illustrated  by  39  Engravings,  338  pages. 

I2mo $3.°° 

BRANNT — The  Practical  Scourer  and  Garment  Dyer: 

Comprising  Dry  or  Chemical  Cleaning ;  the  Art  of  Removing  Stains  ;.. 
Fine  Washing;  Bleaching  and  Dyeing  of  Straw  Hats,  Gloves,  and 
Feathers  of  all  kinds;  Dyeing  of  Worn  Clothes  of  all  fabrics,  in- 
cluding Mixed  Goods,  by  One  Dip ;  and  the  Manufacture  of  Soaps 
and  Fluids  for  Cleansing  Purposes.  Edited  by  WILLIAM  T.  BRANNT, 
Editor  of  "The  Techno-Chemical  Receipt  Book."  Illustrated. 
203  pages.  I2mo.  .....  .  $2.00 

BRANNT.— Petroleum . 

its  History,  Origin,  Occurrence,  Production,  Physical  and  Chemical 
Constitution,  Technology,  Examination  and  Uses;  Together  with 
the  Occurrence  and  Uses  of  Natural  Gas.  Edited  chiefly  from  the 
German  of  Prof.  Hans  Hoefer  and  Dr.  Alexander  Veith,  by  WM. 
T.  BRANNT.  Illustrated  by  3  Plates  and  284  Engravings.  743  pp. 
8vo.  $7-5° 

BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Vine- 
gar and  Acetates,  Cider,  and  Fruit-Wines  : 
Preservation  of  Fruits  and  Vegetables  by  Canning  and  Evaporation; 
Preparation  of  Fruit-Butters,  Jellies,  Marmalades,  Catchups,  Pickles,. 
Mustards,  etc.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated  by  79  Engravings.  479  pp.  8vo.  $6.00 

BRANNT.— The  Metal  Worker's    Handy-Book   of  Receipts 

and  Processes : 

Being  a  Collection  of  Chemical  Formulas  and  Practical  Manipula- 
tions for  the  working  of  all  Metals ;  including  the  Decoration  and 
Beautifying  of  Articles  Manufactured  therefrom,  as  well  as  their 
Preservation.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated.  ismo.  |2.5<r 


HENRY  CAREY  BA1RD   &  CO.'S  CATALOGUE.       31 

OEiTE.—  A  Practical  Treatise   on   the  Manufacture  of  Per* 

lumery. 

Comprising  directions  for  making  all  kinds  of  Perfumes,   Sachef 
Powders,  Fumigating  Materials,  Dentifrices,  Cosmetics,  etc.,  with  a 
full  account  of  the  Volatile  Oils,  Balsams,  Resins,  and  other  Natural 
and    Artificial    Perfume-substances,  including  the   Manufacture  of 
Fruit  Ethers,  and  tests  of  their  purity.     By  Dr.  C.  DEITE,  assisted 
by  L.  BORCHERT,  F.  EICHBAUM,  E.   KUGLER,  H.  TOEFFNER,  and 
other  experts.    From  the  German,  by  WM.  T.  BRANNT.     28  Engrav- 
ings.    358  pages.     8vo.  ......        IS-00 

EDWARDS.  —  American    Marine  Engineer,    Theoretical   anc. 

Practical  : 

With  Examples  of  the  latest  and  most  approved  American  Practice. 
By  EMORY  EDWARDS.  85  illustrations.  I2mo.  .  .  $2.50 

EDWARDS.  —  900    Examination   Questions  and  Answers: 

For  Engineers  and  Firemen  (Land  and  Marine)  who  desire  to  ob- 
tain a  United   States  Government  or  State  License.     Pocket-book 
form,  gilt  edge          ........         $l-5° 

KIRK.  —  The  Cupola  Furnace  : 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foun- 
dry Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter, 
author  of  "The  Founding  of  Metals."  Illustrated  by  80  Engravings. 
8vo.  (1899)  l3'5° 

POSSELT.  —  The  Jacquard  Machine  Analysed  and  Explained: 

With  an  Appendix  on  the  Preparation  of  Jacquard  Cards,  and 
Practical  Hints  to  Learners  of  Jacquard  Designing.  By  E.  A. 
POSSELT.  With  230  illustrations  and  numerous  diagrams.  127  pp. 
4to  ........... 


POSSELT.—  The  Structure  of  Fibres,  Yarns  and  Fabrics: 

Being  a  Practical  Treatise  for  the  Use  of  all  Persons  Employed  in 
the  Manufacture  of  Textile  Fabrics,  containing  a  Description  of  the 
Growth  and  Manipulation  of  Cotton,  Wool,  Worsted,  Silk.  Flax, 
Jute,  Ramie,  China  Grass  and  Hemp,  and  Dealing  with  all  Manu- 
facturers' Calculations  for  Every  Class  of  Material,  also  Giving 
Minute  Details  for  the  Structure  of  all  kinds  of  Textile  Fabrics,  and 
an  Appendix  of  Arithmetic,  specially  adapted  for  Textile  Purposes. 
By  E.  A.  POSSELT.  Over  400  Illustrations,  quarto.  .  $5.00 
RICH.  —  Artistic  Horse-Shoeing: 

A  Practical  and  Scientific  Treatise,  giving  Improved  Methods  of 
Shoeing,  with  Special  Directions  for  Shaping  Shoes  to  Cure  Different 
Diseases  of  the  Foot,  and  for  the  Correction  of  Faulty  Action  in 
Trotters.  By  GEORGE  E.  RICH.  62  Illustrations.  153  pages. 
tamo,  ...  .......  $1.00 


32       HENRY   CAREY   BAIRD   &  CO.'S   CATALOGUE. 

RICHARDSON.— Practical  Blacksmithing : 

A  Collection  of  Articles  Contributed  at  Different  Times  by  Skilled 
Workmen  to  the  columns  of  "  The  Blacksmith  and  Wheelwright," 
and  Covering  nearly  the  Whole  Range  of  Blacksmithing,  from  the 
Simplest  Job  of  Work  to  some  of  the  Most  Complex  Forgings. 
Compiled  and  Edited  by  M.  T.  RICHARDSON. 

Vol.1.  210  Illustrations.  224  pages.  I2mo.  .  .  $1.00 
Vol.  II.  230  Illustrations.  262  pages.  I2mo.  .  .  $1.00 
Vol.  III.  390  Illustrations.  307  pages.  I2mo.  .  .  $1.00 
Vol.  IV.  226  Illustrations.  276  pages.  I2mo.  .  .  $1.00 

RICH ARDSOlir—  The  Practical  Horseshoer: 

Being  a  Collection  of  Articles  on  Horseshoeing  in  all  its  Branches 
which  have  appeared  from  time  to  time  in  the  columns  of  "  The 
Blacksmith  and  Wheelwright,"  etc.  Compiled  and  edited  by  M.  T. 
RICHARDSON.  174  illustrations.  .....  $1.00 

ROPER. — Instructions    and    Suggestions    for   Engineers   and 

Firemen : 
By  STEPHEN  ROPER,  Engineer.     i8mo.     Morocco        .        $2.00 

ROPER. — The  Steam  Boiler:  Its  Care  and  Management: 
By  STEPHEN  ROPER,  Engineer.     I2mo.,  tuck,  gilt  edges.         $2.00 

ROPER. — The  Young  Engineer's  Own  Book: 

Containing  an  Explanation  of  the  Principle  and  Theories  on  which 
the  Steam  Engine  as  a  Prime  Mover  is  Based.  By  STEPHEN  ROPER, 
Engineer.  160  illustrations,  363  pages.  i8mo.,  tuck  .  $2.50 

ROSE. — Modern  Steam -Engines: 

An  Elementary  Treatise  upon  the  Steam-Engine,  written  in  Plain 
language ;  for  Use  in  the  Workshop  as  well  as  in  the  Drawing  Office. 
Giving  Full  Explanation  3  of  the  Construction  of  Modern  Steanv 
Engines :  Including  Diagrams  showing  their  Actual  operation.  To- 
gether with  Complete  but  Simple  Explanations  of  the  operations  of 
Various  Kinds  of  Valves,  Valve  Motions,  and  Link  Motions,  etc., 
thereby  Enabling  the  Ordinary  Engineer  to  clearly  Understand  the 
Principles  Involved  in  their  Construction  and  Use,  and  to  Plot  out 
their  Movements  upon  the  Drawing  Board.  By  JOSHUA  ROSE.  M.  E. 
Illustrated  by  422  engravings.  Revised.  358  pp.  .  .  #6.00 

ROSE. — Steam  Boilers: 

A  Practical  Treatise  on  Boiler  Construction  and  Examination,  for  the 
Use  of  Practical  Boiler  Makers,  Boiler  Users,  and  Inspectors ;  and 
embracing  in  plain  figures  all  the  calculations  necessary  in  Designing 
or  Classifying  Steam  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  73  engravings.  250  pages.  8vo.  .  .  .  .  $2.50 

BCHRIBER.— The  Complete  Carriage  and  Wagon  Painter: 
A  Concise  Compendium  of  the  Art  of  Painting  Carriages,  Wagons, 
and  Sleighs,  embracing  Full  Directions  in  all  the  Various  Branches, 
including  Lettering,  Scrolling,  fcmansenting,  Striping,  Varnishing, 
and  Coloring,  with  numerous  Recipes  for  Mixing  Colors.  73  Illus- 
trations. 177  pp.  I2mo.  ......  $i.OO 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
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AN     INITIAL     FINE     OF    25     CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
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UMT       MINLJ       HJ      :>1.UU      WIN        lilt.      at.Vt.IN  1  l-l       LJ  A  Y 

OVERDUE. 

JAN   231933 

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